Return to Work Safely Webinar

September 16, 2021
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Our leading industrial hygienist and environmental engineer will be speaking on the following topics:

  1. How The Molecule That Gives Us Energy Can Help Assess Contamination and Surface Cleaning Practices
  2. Drinking Water 101
  3. The New Hybrid Work Environment: How Ergonomics is More Important Now Than Before.
  4. Demystifying Air Exchange Rates in Indoor Air Quality and Ventilation.

When: Tuesday, September 21st, 1 PM EST 

Register here: https://lu.ma/THEMRTW

Ergonomic Risk Factors and Injuries in the Office

May 27, 2021
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There are multiple risk factors that can contribute to musculoskeletal injuries from exposure to ergonomic hazards while performing office work at home or in the office. What these risk factors all have in common is that they work to cause musculoskeletal disorders, psychosocial health effects, and reduce the quality of life outside of working hours. Risk factors come from many aspects of the workstation, task, and individual worker. They can be grouped into three main categories which are biomechanical, task-specific, and individual worker characteristics. When conducting an office ergonomic assessment for a workstation and task, the factors mentioned below are what are assessed, and controlled.

Biomechanical risk factors are present when workers perform tasks that require heavy lifting and/or excessive repetition, and awkward or static postures (1). These factors put excessive strain on the tissues of the body. Over time, the accumulated strain can result in an injury or the development of discomfort/pain. What all these factors have in common is that they remove the body from its neutral posture and loads are displaced unevenly throughout the body as a result. For excessive repetition to cause harm it does not require the lifting of heavy objects. Excessive repetition regardless of forces required to perform the movement can cause injury. One of the most common musculoskeletal disorder in the world is Carpal Tunnel Syndrome. Often this injury is associated with repetitive finger movements such as clicking and typing, in combination with compression of the wrist against a work surface. The repetitive motions result in the tissues becoming irritated and then inflamed, once inflamed the space in the carpal tunnel is reduced and the median nerve becomes compressed. The loss of sense and slight reduction in movement is a result of stress on the tissues of the wrist even though the actions require minimal amounts of force to be produced.

Task-specific risk factors include, workstation layout, high physical work, work that has high psychosocial demands, or work that requires prolonged use of visual displays. These factors are more closely associated to the requirements of the tasks being performed by the workers. Workstation layout is extremely important as it is a combination of furniture and organization of materials. A worker using a chair that has very low adjustability and support can remove the worker’s body from a neutral seated posture for extended or short and frequent periods of time. Combining a poorly suited office chair with a desk or work surface that is poorly organized can make the worker reach for items such as a mouse or keyboard. When reaching to use the mouse the worker is then in a static reaching position for a period of time which can put unhealthy stress on the tissues of the shoulder for example. Most of our working time when seated at a desk is spent using some type of visual display, being a cell phone or computer screen. Nowadays, we spend most of our time looking at a screen; without knowing the position of the screen in relation to our body plays a massive role in the risk of a musculoskeletal injury as a result of this.

Often forgotten but extremely important to consider is that workers come in all sizes. Therefore, there is hardly ever a workstation design that is a one-size fits all design. A common phrase to go by when designing a workstation or task setup is to “design it for the worker since you cannot design the worker to the workstation or task”. No two workers are the same thus when ergonomics are considered, individual worker characteristics such as smoking, a high body mass index, anthropometry, and other co-morbidities which include non-occupational related injuries are ergonomic risk factors too (1, 2). These factors are difficult to prevent from being introduced into the workspace, but their effects can be mitigated once identified. A worker’s anthropometry is an extremely important risk factor that must be considered. A workstation for a worker who is 5’2” should differ dramatically from a workstation for a worker who is 5’10”. If the workstation was designed for the taller individual in mind, the smaller worker will be required to reach or lean forward much more frequently for example. When a worker has to reach to perform their task, the risk of injury from exposure to an ergonomic hazard is significantly higher than a worker who does not have to reach to perform the same task.

This list of risk factors for exposure to ergonomic hazards is not fixed, as every situation presents other unique challenges and risks that are identified and assessed on a case-to-case basis. This is why it is extremely important to have objective and competent professionals performing ergonomic assessments.

Summary & Keywords

  • Ergonomics
    • Factors in the environment that can cause damage to the musculoskeletal system.
  • Objectives of Ergonomic Assessments
    • Identify risk factors
    • Quantify the risk
    • Control the risk
  • Three main risk factor categories
    • Biomechanical
      • Movements the worker performs while at the workstation or completing the task.
    • Task-specific
      • Characteristics of the workstation such as organization of items and materials, and the size of the furniture.
      • Psychophysical demands of the task.
        • Highly stressful tasks can cause muscle fatigue more rapidly leading to poor postures and headaches.
      • Use of visual displays.
        • The positioning of visual displays and the characteristics of them can cause workers to lean forward to read text, constant re-focusing when looking at a screen and documents. This can lead to neck, back, and eye strains.
        • High physical work.
          • This is deceiving as a task does not require constant movement of heavy loads or the generation of high forces to be considered high physical work. 54 – 75% of a working day is spent typing, that is a lot of movements in the arm and fingers. These repetitive low force movements do pose a risk of musculoskeletal injury to workers.
    • Individual worker characteristics
      • Anthropometry and Body Mass Index
        • Workers come in all different shapes and sizes, it is important to take this into consideration when designing a workspace or task.
          • Fit the task and workspace to the worker.
      • Smoking
        • Indirectly increases your risk of musculoskeletal injury as this affects many of the systems in your body.
      • Other co-morbidities
        • Disabilities resulting from injuries that are work or non-work related. If a worker has a previous non-work related injury and this impacts the way they should be normally performing the task, most often the worker will compensate for this by altering the movements the body. This change in movements may introduce new risks that were not present before the injury and require identification and control to prevent further injury.


  • How can I identify these risks in my workplace?
    • On our website www.tharris.ca we have a complementary video that walks our clients through what to look for to identify ergonomic risks at a workstation. If you are unsure always feel free to reach out to us at T.Harris Environmental Management with any questions and we will be very glad to help you with that.
  • Which of these risk factors is most important?
    • All of them are very important. Each workplace will have their own unique risk factors but the main group of risk factors that is consistent throughout any workplace are the task-specific risk factors. These factors are a combination of task requirements and workstation design.
  • Why are these risk factors important?
    • Most of these risk factors are work related but the effects as a result of exposure to them extend to life outside of work. Musculoskeletal injuries and other health effects that arise from ergonomic hazard exposure can seriously dampen an individual’s quality of life.
  • How do I know the pain the worker is feeling is from ergonomic hazard exposure?
    • First thing you ask the worker is, “Does the pain worsen as the week goes on, and lessens on the weekend or during time off?”
      • If they say yes, then this is an indication that the pain is a result of ergonomic hazard exposure during work related tasks.
    • Second thing you ask the worker is, “Do you feel uncomfortable at your workstation or while performing this task?”
      • If they say yes, this is an indication that the workstation or task requirements remove the worker from a neutral position for long periods of time or for short frequent periods. This can eventually lead to musculoskeletal injury development.


1. Da Costa BR, Vieira ER. Risk factors for work-related musculoskeletal disorders: a systematic review of recent longitudinal studies. American Journal of Industrial Medicine 53: 285–323, 2010. doi: https://doi.org/10.1002/ajim.20750.
2. Klussmann A, Gebhardt H, Liebers F, Rieger MA. Musculoskeletal symptoms of the upper extremities and the neck: A cross-sectional study on prevalence and symptom-predicting factors at visual display terminal (VDT) workstations. BMC Musculoskeletal Disorders 9: 96, 2008. doi: 10.1186/1471-2474-9-96.

Benefits of Workplace Ergonomic Assessments

May 26, 2021
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Ergonomic assessments are used in workplaces as a measure of risk relating to musculoskeletal injury development. Musculoskeletal injuries are estimated to cost the Canadian economy upwards of $22 billion each year (1). In developed economies such as Canada’s, nontraumatic musculoskeletal injuries incur direct and indirect economic costs of approximately $500 million per 1 million workers (2). To reduce this economic burden, ergonomic assessments can be one of the tools individuals and businesses can use to do so.

Currently, with the ever changing restrictions due to the COVID-19 pandemic, performing office work from home is becoming more prominent and normalized. Many workers may not have a designated office space that is setup similarly to that of their workstation in the company office. With this comes new challenges with regards to ergonomic hazard exposure and worker safety. Although new challenges arise, the responsibilities are unchanged; the responsibilities outlined in the Ontario Occupational Health & Safety Act still apply whether or not the worker is working from home or in the company’s offices. Therefore under clause 25(2)(h) of the Occupational Health and Safety Act, it is the employer’s responsibility to take every precaution reasonable in the circumstance to ensure the safety and health of their worker (3) . In these current situations, legally it is beneficial for the employer to have ergonomic hazard risk assessments of their employee’s workspace when working from home to ensure their safety and health is not compromised.

The goals of an ergonomic assessment are to identify the physical and psychosocial risk factors of the workstation and associated task, quantify the risk, and make the necessary adjustments to the workstation or task to minimize this risk. When thinking about workplace ergonomics, initially we think about three things. First, we think about lower back pain, which is then followed by sitting for long periods of time, then finally office chairs. In this case, lower back pain occurs as a result of exposures to ergonomic hazards; these include being seated in a static posture for a long period of time and the type of office chair being used. Although these are the risk factors, they can also be part of the solution. Assessing the current workspace furniture and tasks can help control the exposures to ergonomic hazards resulting in benefits for the user and the business.

To protect workers from ergonomic hazards, the magnitude of exposure must be identified, assessed, and then controlled. To do so, professionals in the field of occupational health and safety follow CSA Z412-17 Office Ergonomics – An application standard for workplace ergonomics. If done by an objective and competent individual, the benefits of an ergonomic assessment can be recognized at an organization level and at the individual worker level.

For the benefits an organization will see, studies have found that after ergonomic assessments and training are performed for workers on a whole the organizations observed (4–6):

  • Increased output per worker
  • Reduction in errors
  • Reduced accidents, injuries, and illnesses resulting in lost time
  • Reduced turnover and absenteeism
    • With this, there is a reduction in time spent training new employees
  • Reduced worker compensation costs

For the benefits the individual worker will see, studies have found that after ergonomic assessments or ergonomic hazard awareness training workers experienced (7–17):

  • Reductions in pain incidence or severity in multiple regions of the body
    • Lower back
    • Shoulder
    • Neck
  • Significant increase in overall ergonomic knowledge which led to lower rates of work-related musculoskeletal injuries

Summary & Keywords

  • Ergonomics
    • Factors in the environment that can cause damage to the musculoskeletal system.
  • Objectives of Ergonomic Assessments
    • Identify risk factors
    • Quantify the risk
    • Control the risk
  • Organization benefits
    • Increased output per worker
    • Reduction in errors
    • Reduced accidents, injuries, and illnesses resulting in lost time
    • Reduced turnover and absenteeism
      • With this, there is a reduction in time spent training new employees
    • Reduced worker compensation costs
  • Individual worker benefits
    • Reductions in pain incidence or severity in multiple regions of the body
      • Lower back
      • Shoulder
      • Neck
    • Significant increase in overall ergonomic knowledge which led to lower rates of work-related musculoskeletal injuries
  • Occupational Health & Safety Act
    • Legislation passed in 1978 that gives everyone in the system responsibility for health and safety.
    • Sets requirements for Joint Health and Safety Committees in organizations dependent on employee populations.
    • Clause 25(2)(h) states the employer shall “take every precaution reasonable in the circumstance for the protection of a worker.”


  • Will I see the benefits of ergonomic assessments right away?
    • Yes and no. If an ergonomic assessment is done as a proactive measure before musculoskeletal disorders are present, the benefits may never be realized because worker injury has been avoided. If an ergonomic assessment is done as a result of a worker having developed a musculoskeletal disorder, the benefits at the individual level may be seen quickly as the pain they experience may be reduced dramatically. At the organization level, the benefits will be seen quickly as the pattern of productivity positively changes and the chance of the worker missing time due to injury is significantly reduced.
  • As an employer, why am I responsible for what the worker does at home?
    • Technically, if company policy provides the worker with the opportunity to work from home, their home is now a part of their workplace. Under clause 25(2)(h) in the Occupational Health and Safety Act, the employer is responsible to ensure the worker’s place of work is safe.
  • How do I know if a workstation requires an ergonomics assessment
    • All workstations should have an ergonomics assessment done to assess the risk. It is possible that the assessment concludes the current setup and task requirements pose little to no risk of musculoskeletal disorder development in the user. This information is still very valuable as it shows the company has been done their due diligence to ensure the worker is safe.


1. Canadian Institutes of Health Research, Government of Canada. IMHA Strategic Plan 2014-2018 – CIHR [Online]. 2019. https://cihr-irsc.gc.ca/e/48830.html [16 Feb. 2021].
2. Lambeek LC, van Tulder MW, Swinkels ICS, Koppes LLJ, Anema JR, van Mechelen W. The Trend in Total Cost of Back Pain in the Netherlands in the Period 2002 to 2007: Spine 36: 1050–1058, 2011. doi: 10.1097/BRS.0b013e3181e70488.
3. Government of Ontario. Occupational Health and Safety Act, R.S.O. 1990, c. O. 1 [Online]. https://www.ontario.ca/laws/statute/90o01: 2014. https://www.ontario.ca/laws/view.
4. Hendrick HW. Determining the cost–benefits of ergonomics projects and factors that lead to their success. Applied Ergonomics 34: 419–427, 2003. doi: 10.1016/S0003-6870(03)00062-0.
5. Schlesinger L, Heskett J. The service-driven service company. Harv Bus Rev 69: 71–81, 1991.
6. Goggins RW, Spielholz P, Nothstein GL. Estimating the effectiveness of ergonomics interventions through case studies: Implications for predictive cost-benefit analysis. Journal of Safety Research 39: 339–344, 2008. doi: 10.1016/j.jsr.2007.12.006.
7. Robertson M, Amick BC, DeRango K, Rooney T, Bazzani L, Harrist R, Moore A. The effects of an office ergonomics training and chair intervention on worker knowledge, behavior and musculoskeletal risk. Applied Ergonomics 40: 124–135, 2009. doi: 10.1016/j.apergo.2007.12.009.
8. Amick BC, Robertson M, DeRango K, Bazzani L, Moore A, Rooney T, Harrist R. Effect of Office Ergonomics Intervention on Reducing Musculoskeletal Symptoms: Spine 28: 2706–2711, 2003. doi: 10.1097/01.BRS.0000099740.87791.F7.
9. Amick BC, Menéndez CC, Bazzani L, Robertson M, DeRango K, Rooney T, Moore A. A field intervention examining the impact of an office ergonomics training and a highly adjustable chair on visual symptoms in a public sector organization. Applied Ergonomics 43: 625–631, 2012. doi: 10.1016/j.apergo.2011.09.006.
10. Bohr PC. Efficacy of Office Ergonomics Education. J Occup Rehabil 10: 243–255, 2000. doi: 10.1023/A:1009464315358.
11. Hoe VC, Urquhart DM, Kelsall HL, Sim MR. Ergonomic design and training for preventing work‐related musculoskeletal disorders of the upper limb and neck in adults. Cochrane Database Syst Rev 2012, 2012. doi: 10.1002/14651858.CD008570.pub2.
12. Haukka E, Pehkonen I, Leino-Arjas P, Viikari-Juntura E, Takala E-P, Malmivaara A, Hopsu L, Mutanen P, Ketola R, Virtanen T. Effect of a participatory ergonomics intervention on psychosocial factors at work in a randomised controlled trial. Occupational and environmental medicine 67: 170–177, 2010.
13. Haukka E, Leino-Arjas P, Viikari-Juntura E, Takala E-P, Malmivaara A, Hopsu L, Mutanen P, Ketola R, Virtanen T, Pehkonen I, Holtari-Leino M, Nykänen J, Stenholm S, Nykyri E, Riihimäki H. A randomised controlled trial on whether a participatory ergonomics intervention could prevent musculoskeletal disorders. Occupational and Environmental Medicine 65: 849–856, 2008. doi: 10.1136/oem.2007.034579.
14. Laing A, Cole D, Theberge N, Wells R, Kerr M, Frazer M. Effectiveness of a participatory ergonomics intervention in improving communication and psychosocial exposures. Ergonomics 50: 1092–1109, 2007. doi: 10.1080/00140130701308708.
15. Laing A, Frazer M, Cole D, Kerr M, Wells R, Norman R. Study of the effectiveness of a participatory ergonomics intervention in reducing worker pain severity through physical exposure pathways. Ergonomics 48: 150–170, 2005. doi: 10.1080/00140130512331325727.
16. Stock SR, Nicolakakis N, Vézina N, Vézina M, Gilbert L, Turcot A, Sultan-Taïeb H, Sinden K, Kin R, Denis M-A, Delga C, Beaucage C. Are work organization interventions effective in preventing or reducing work-related musculoskeletal disorders? A systematic review of the literature. Scandinavian Journal of Work, Environment & Health 44: 113–133, 2018.
17. Mahmud N, Kenny DT, Md Zein R, Hassan SN. Ergonomic Training Reduces Musculoskeletal Disorders among Office Workers: Results from the 6-Month Follow-Up. Malays J Med Sci 18: 16–26, 2011.

What is Ergonomics?

May 01, 2019
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While talking to my friends, a group of healthy 20-25 year-old university graduates who have recently entered the workforce, I was surprised to learn how common back and muscle pain due to studying and deskwork had become. As all of us were joking about how we felt like we were unhealthy and working labour intensive jobs, I could not help but recognize that this is a serious yet neglected issue.

When we think of why body aches and pains have become so common, often the answer that comes to mind is awkward posture, or working for too long. While these are contributing factors, there are a wide variety of elements at play. A specific field of study, called ergonomics, actually addresses these concerns. Many of us have heard the term and perhaps just never paid much attention to it, until it is too late!

Whether you work at a desk or in a more physically demanding role or anywhere in between, T. Harris Environmental Management Inc. (THEM) can help make sure your work isn’t hurting you. If you have questions about how we can help, call us at 1-888-ASK-THEM.


In a nutshell ergonomics is the process by which any task is adjusted to fit the person’s physical and mental capabilities to alleviate stress and/or strain, and as such, avoid ergonomic related injuries. Ergonomics is not just limited to the position of your chair, or the placement of your desk. It can be applied to everything we do in life; even sleeping. Thus, when applying ergonomics in the workplace the task is fitted to the worker, and when designing consumer items the products are matched to the target users.


Unfortunately, many of us take minor back pain, muscle cramps, and stiffness lightly, as it is commonly observed in many of our family and friends. Some of us choose to ignore it as “we just do not have time for it”.

However, pains and cramps due to poor/awkward posture, repetitive tasks, exposure to vibrations, and forceful exertions in labor intensive tasks, are a serious workplace hazard. In fact, lower back pain from poor ergonomically designed job tasks is a very common workplace injury, and in some parts of the world it is the most common work-related disability. This means that poor office ergonomics not only affects the employees long-term, but also reduces the overall productivity of the company, and thereby also reduces profits.  As an employer you may suffer direct and indirect costs, such as; increase in insurance coverage, loss of reputation/credibility, and in employee (turnover).

To put this into perspective, according to the Public Services Health and Safety Association (PSHSA):

  • 1 in every 10 Canadian adults has experienced Musculoskeletal Disorder (MSD) that has limited their normal activities.

  • 30% lost-time claims were due to MSDs in Ontario in 2016.

  • MSDs have been the most common type of work injury over the past 10 years.


T. Harris Environmental Management can help you make the most out of your workstation while keeping your staff healthy! Email us at info@tharris.ca to request a free consultation!


Poor posture, repetitive tasks, and forceful physical exertions can lead to the development of a broad range of disorders called Musculoskeletal Disorders (MSDs), or Repetitive Strain Injuries (RSIs). Essentially, when our muscles, joints, and tendons are repeatedly exerted and stressed they eventually become damaged and can become irreversible. Thus, acute pain felt for a few hours can actually develop into serious and chronic problems.

Common examples of such injuries include:

  • Carpal Tunnel Syndrome

  • Back injuries

  • Tendinitis

  • Raynaud’s syndrome (White Finger)


Common symptoms experienced by workers include:

  • Swelling

  • Acute and chronic pain

  • Stiffness

  • Reduction in range of motion

  • Inflammation

  • Eye strains


As an employer:

As work-related injuries due to poor ergonomics can substantially impact your employees’ wellbeing and company’s economic standing, investing in an Office Ergonomic Program can be highly beneficial.

An ergonomics professional, such as an Occupational Hygienist, can help create customized solutions to address your ergonomic concerns. This involves performing an in-depth review of all aspect of the environment that would effect a workers comfort, and also recommend control measures to prevent future injuries.

Services can include:

  • A thorough analysis of a worker’s environment; such as their

    • Job task

    • Frequency and duration

    • Lighting conditions

    • Tools/equipment used

    • Posture used and force exerted

    • Exposure to vibration and extreme temperatures

    • Reach and range of motion to commonly used items

  • A program that addresses worker’s unique needs and fit the task to each worker by following best practices published in reputable standards and guidelines.

  • Training that allows employers to become self-sufficient when evaluating the ergonomics of their day-to-day tasks, and provide recommendations for ergonomic work practices, such as lifting and stretching exercises.


When your Occupational Hygienist completes your new Office Ergonomic Program you can expect benefits such as:

  • Increased productivity and efficiency

  • Increased overall health, well-being and employee morale

  • Decrease in work-related injuries such as MSDs

  • Decreased indirect and direct costs to employers

As an Employee:

Ask your employer if there is an Office Wellness and/or Ergonomic Program in place. Recognize signs and symptoms of MSDs and report them to your employer. If you notice there is a task/activity that is uncomfortable, let your employer know so they can adjust the task. Finally, follow recommendations on best ergonomic practices, such as taking regular breaks, for your health and safety!

With benefits like this, why wouldn’t you make the move for better workplace ergonomics?

 1-888-ASK-THEM  |  www.tharris.ca  | info@tharris.ca

Edmonton | London | Toronto | Ottawa | Montreal



  • CCOHS.ca. (2019). (Canadian Centre for Occupational Health and Safety). [online] Available at: https://www.ccohs.ca/oshanswers/ergonomics/ [Accessed 7 Feb. 2019].

  • DiNardi, S. R. (1997). The occupational environment: Its evaluation and control. Fairfax, VA: AIHA Press.

  • PSHSA.ca. (2018). (Public Services Health and Safety Association). [online] Available at: https://www.pshsa.ca/ergonomics/ [Accessed 7 Feb. 2019].

Why The Concern About Manganese In Welding?

September 19, 2018
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There are significant concerns about potential neurological effects associated with exposure to manganese in welding fumes.   Welding fumes are composed of metals and most fumes contain a small percentage of manganese.  Manganese may be found in carbon steel shielded metal arc welding (SMAW or stick) electrodes as part of the flux coating on the welding rod, as a flux in carbon steel flux core arc welding (FCAW) and as a filler metal in gas metal arc welding (GMAW or MIG) wire.   It is present in recycled carbon steel and used in abrasion resistant applications such as ball mills or earth moving equipment.   Manganese has a substantially lower boiling point than iron, therefore, it will vapourize more easily than iron leading to a higher presence on a percentage basis in welding fumes than in the original wire.

Current research on the effects of manganese in welding on health.

Recent studies indicate neurological and neurobehavioral deficits may occur when workers are exposed to low levels of manganese (<0.2 mg/m3) in welding fumes. These effects include changes in mood and short-term memory, altered reaction time, and reduced hand-eye coordination. Affected workers frequently show abnormal accumulations of manganese in a region of the brain known as the globus pallidus. The globus pallidus plays an important role in movement regulation[1].

The onset of motor fluctuations and dyskinesia among welders occurred at a mean age of 46 compared to a mean age of 63 among non-welder controls. Dyskinesia refers to a category of movement disorders that are characterized by involuntary muscle movements, including movements similar to tics or chorea and diminished voluntary movements.   Also observed were decrements in verbal learning, working memory, cognitive flexibility, visuomotor processing speed and motor efficiency[2].   Five measures of eye-hand coordination (precision, percent precision, imprecision, percent imprecision, and uncertainty) reflected more erratic control of fine hand-forearm movement in a manganese-exposed group than the control group.

Regulations are not keeping up with the science.

In February 2013, the American Conference of Governmental Industrial Hygienists (ACGIH) recommended a decrease in the time weighted average (TWA) (measured over an eight hour shift) threshold limit value (TLV) for respirable manganese particulate of 0.2 mg/m3 to 0.02 mg/m3 which represents a tenfold reduction[3].    The respirable fraction is the smallest particulate fraction sampled and is less than 4 µm mass median aerodynamic diameter, which covers the particulates typically found in welding fumes.

The ACGIH also issued a guidance of 0.1 mg/m3 TWA inhalable manganese particulate that can be inhaled into the nose and mouth but not likely to be inhaled into the deep lungs because of size. These larger particulates are normally associated with grinding operations instead of welding.

The problem is that five years later, provincial regulatory limits have not kept pace with the current science.   These regulations do not account for the higher toxicity of ultrafine manganese particulates found in welding fumes, which can deposit deep in the lung alveoli and are capable of passing directly into the blood stream.  Ontario Regulation 833 currently limits manganese exposure to 0.1 mg/m3 TWA total particulate.  Similarly, Quebec Regulation respecting occupational health and safety (Chapter S-2.1, s.223) limits manganese exposure to 0.2 mg/m3 TWA total particulates and is not protective enough for manganese.  Alberta Regulation 87/2009 amended June 1, 2018 also limits manganese exposure to 0.2 mg/m3  TWA total particulate.

What is the bottom line for manganese?

As this article shows, current provincial limits do not provide sufficient protection, so it is wise for employers to take measures to protect worker above and beyond the regulatory limit. Here are some steps you can take:

  • Welders should use portable or fixed local exhaust ventilation (LEV).
  • Welders should wear respiratory protection (half face air purifying respirator with P100 filter)
  • Employers should substitute for Hobart low manganese GMAW wire. Mn is reduced about 1/3 from regular wire
  • Employers should assess worker airborne exposure to manganese in welding
  • Occupational exposures should be controlled to meet more protective ACGIH OELs
  • A manganese control program should be developed for welding processes.
  • Annual air exposure monitoring should be performed to verify controls are effective.
  • A regular review of LEV should be conducted to ensure engineering controls are effective

T. Harris Environmental Management Inc. has experienced occupational hygienists and occupational hygiene technicians to help you assess your welding shop to ensure that you practice ‘due diligence’ to safeguard the health and safety of your welding personnel.


[1] https://www.cdc.gov/niosh/topics/welding/default.html

[2] AIHA Fall Conference 2015, PDF 3: Welding: Identifying Exposures and Controls, Orlando Oct. 26-27, 2015

[3] https://www.thefabricator.com/article/arcwelding/new-guideline-reduces-manganese-exposure-limit-dramatically

Here is how radon can affect your business! 

September 19, 2018
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Authors: Christopher Nielsen & Angeline Snow

Radon Risk

Although there is still a high percentage of the Canadian population that is not aware of Radon or its associated health risks, awareness has been increasing in recent years.

It is crucial to know how radon gas affects human health.  According to Statistics Canada, 7% of homes have high levels of radon.  This is of particular concern as radon is the second-leading cause of lung cancer, after smoking, and accounts for 16% of lung cancer deaths, or 3,200 deaths, in Canada every year.  The radioactive radon particles in the air can get lodged in our lung tissues when they are inhaled.  The energy released by the radioactive particles then damages the lung cells.

If you are thinking that this cannot happen in your building, think again.  Although the home is a common source of significant exposure, radon can represent a hazard in any building particularly in areas with high natural radon levels or in basements or areas with limited air circulation.  Radon is a colourless, odourless radioactive gas that is formed by the breakdown of naturally-occurring uranium in soil, rock and water.  It can find its way into nearly any building and can build-up in enclosed spaces.  Radon enters buildings through the foundation or drinking water system and tends to be found at the highest concentrations at lower levels of a building, particularly below ground level.  And it is undetectable by human senses.  The only way to determine if this risk exists in your space is to test your home or office.

Legal Liabilities and Radon

As a naturally occurring gas, radon is different from most other air quality problems: while its existence is not the fault of anyone, its accumulation inside a building at dangerous levels can be easily avoided.  Adherence to best practices in building design, construction and renovation provide the necessary solutions and testing is the first step to reduce the risk.  Health Canada has established a guideline for residential buildings of 200 Bq/m3 (becquerels per cubic metre).   In general, it recommends remedial measures should be undertaken in a dwelling whenever the average annual radon concentration exceeds 200 Bq/m3 in the normal occupancy area.  When remedial action is taken, the radon level should be reduced to a value as low as practicable.  It also stipulates that the construction of new dwellings should employ techniques that will minimize radon entry and will facilitate post-construction radon removal, should this subsequently prove necessary. There are other ways to reduce the level of radon in a building including fixing cracks in floors and sub-grade walls, providing better ventilation, closing entry routes, replacing the furnace and depressurizing the space below the basement floor slab.

There are currently no legal requirements addressing radon specifically but several provinces, including Ontario, have considered legislation to address the issue.  Currently, there are three possible theories of liability that may apply in case of radon exposure situations in public buildings: (i) negligence, (ii) products liability, and (iii) fraud and misrepresentation. Potential defendants include the owner or occupier, those involved in new construction and renovations (architects, contractors, engineers), and those involved in the sale of property (real estate agents, brokers, home inspectors). There are also several kinds of warranties (express and/or implied) that are inherent in real estate transactions. The implied warranty of habitability – that is, the assumed assurance of the buyer (or lessee) that the seller or lessor of a property is promising that the property is suitable for its intended purposes – is relevant in the case of radon in indoor air.

Duties of the Building Owner/Manager

All building owners are liable for the safety of those making use of their property and buildings. Failure to notify building users of high indoor radon levels, or remediate any known, radon-related risk, building owner(s)/manager(s) could be found liable for the consequences.

Depending on the type of building and the building owner, additional legal duties may be imposed. For example, school boards, landlords, and employers have specific duties with respect to ensuring a healthy and safe environment.  In most Provinces, there is a requirement that employers provide a safe environment for all workers. In Ontario, for example, the general duty clause of Ontario’s Occupational Health and Safety Act (OHSA), clause 25(2)(h), states that an employer must take every precaution reasonable in the circumstances for the protection of a worker. This would include protecting workers form elevated levels of radon.  For commercial establishments, the Canadian Guidelines for the Management of Naturally Occurring Radioactive Materials (NORM Guideline) are considered the industry standard for NORM protection in workplaces.

Please note that the above is not legal advice. For a case-specific legal opinion please seek independent legal advice.

Is there a problem in my building?

In order to determine if radon is present at dangerous levels, one of the multiple testing methods available should be used.  Some people are hesitant to conduct radon testing because they are under the impression that it will be invasive – they will have to rip apart their basements – and that it will be expensive.  In fact, the costs are very reasonable and the testing will only have to be conducted once if the findings indicate there are no elevated levels of radon present.

There are various test kits available commercially and online for the do-it-your-self crowd, but it is important that the tests be conducted properly in order to ensure accurate results.  Based on the potential cancer risk associated with radon, it is advisable to hire an expert to ensure the tests are done properly to ensure accurate results.  Make sure to hire a certified mitigator for testing.  Two common testing devices used for long-term testing are the Alpha Track Detector (1-12 months) and the Long-Term Electret Ion Chamber (1-12 months).

Although short-term tests may indicate if a significant problem exists, they are not recommended due to the high potential for inaccurate results.  A long-term test is much more accurate as levels of radon in a building will vary over time.  A minimum of three months is recommended and a full year (12 month) test period is best.  If you want to conduct a shorter duration test, it should be done during the heating season when levels may be highest.  Also, the testing should preferably be conducted in the lower levels of the building as the chances of radon built-up are much higher in the basements than in the upper floors.

Knowledge is Power!

As awareness of this invisible threat to the public safety increases, steps are being taken to reduce the hazard.  The first step in this process is to educate yourself and to determine if there is a radon hazard in your home or office, or engage a professional consultant to assist you.  The testing process is not invasive, is relatively inexpensive, and will ensure that you understand the radon risk in your environment.  Every step you take to protect your health and reduce your risk factors is a positive one.  Be aware, and be safe.


  1. Health Canada. (2016, January). Guide for Radon Measurement in Public Buildings. Retrieved from: https://www.canada.ca/content/dam/hc-sc/migration/hc-sc/ewh-semt/alt_formats/hecs-sesc/pdf/pubs/radiation/radon_building-edifices/27-15-1468-RadonMeasurements_PublicBuildings-EN13.pdf
  2. Health Canada. (2008). Guide for Radon Measurement in Residential Dwellings (Homes). Retrieved from: https://www.canada.ca/content/dam/hc-sc/migration/hc-sc/ewh-semt/alt_formats/hecs-sesc/pdf/pubs/radiation/radon_homes-maisons/radon_homes-maisons-eng.pdf
  3. Government of Canada. (2017, November 22). Radon: Frequently Asked Questions. Retrieved from: https://www.canada.ca/en/health-canada/services/environmental-workplace-health/radiation/radon/radon-frequently-asked-questions.html#affect-health
  4. Government of Canada. (2013) Canadian Guidelines for the Management of Naturally Occurring Radioactive Materials (NORM).  ISBN: 978-1-100-23019-1, Cat. No.: H129-34/2013E-PDF, 130465.  Retrieved from: https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/environmental-contaminants/canadian-guidelines-management-naturally-occurring-radioactive-materials-norm-health-canada-2000.html
  5. Canada, H. (2018). Radon – Reduction Guide for Canadians – Canada.ca. Retrieved from https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/radiation/radon-reduction-guide-canadians-health-canada-2013.html
  6. Understanding Radon Remediation – A Householder’s Guide – Retrieved from https://www.epa.ie/pubs/reports/radiation/RPII_Guide_Radon_Remediation_Householders.pdf
  7. Canadian Environmental Law Association. (November 2014) B.Dunn, K. Cooper. Radon in Indoor Air: A Review of Policy and Law in Canada. Retrieved: https://www.cela.ca/sites/cela.ca/files/Radon-Report-with-Appendices-Table-pg37-corrected.pdf

Clear The Air: Addressing Exposure To Diesel Engine Exhaust

August 09, 2018
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diesel exhaust

Managers are frequently aware of the risks of associated with some popularized occupational exposures such as asbestos and radon, yet few think about diesel engine exhaust is one of the potent risk factors for developing cancer. It is a serious concern: according to Carex[1], approximately 897,000 Canadians are exposed to diesel engine exhaust at work. This exposure occurs primarily in transportation-related occupations, including truck drivers, bus and subway drivers, locomotive engineers, and bus garage workers, trucking company workers, forklift operators, firefighters, garage attendants, traffic controllers, mechanics, taxi drivers, couriers and professional drivers. In fact, Health Canada[2] attributes an estimated 80% of particulate matter PM10 in the transportation sector to diesel engines. Other workplaces with a significant risk of occupational exposures include mining, construction, rail, farming and military.

The health effects and mechanics of diesel engine exhaust.

What exactly is diesel exhaust and what makes it dangerous? The International Agency for Research on Cancer (IARC)[3] has classified diesel engine exhaust as Group 1, which means it is carcinogenic to humans, based on sufficient evidence for lung cancer. The danger hides in the particulate matter contained in diesel engine exhaust.  Studies have shown increased rates of lung cancer when inhaling whole engine exhaust while other studies where the particulates were removed were inadequate to determine carcinogenicity.

The science and mechanics behind the results of the studies are somewhat complicated. Diesel engine exhaust (DEE) is a complex mixture[4] of substances characterized by polycyclic aromatic hydrocarbons (PAH) surrounding an elemental carbon core.  The gas phase chemicals present in diesel exhaust include nitrogen oxides carbon monoxide and volatile organic compounds such as benzene and formaldehyde. The particulate fraction comprises elemental carbon and organic carbon, ash, sulfate and metals.  Polycyclic aromatic hydrocarbons and nitroarenes are distributed within the gas and particulate phases. PAHs are easily absorbed onto the elemental carbon particulate, which has a large surface area, and are likely the cause of carcinogenicity for diesel engine exhaust.

Even a short-term workplace exposure to diesel engine exhaust can harmful to human health.  It can irritate the eyes, throat, and bronchi, and cause light-headedness, nausea, and respiratory symptoms. Moreover, diesel exhaust may initiate allergic reactions or increase immunological response to other allergens. Upsurges in hospital admission, higher incidence of respiratory symptoms, and decreases in lung function are all associated with exposures to airborne particulate matter, including diesel particulate matter.

Controlling diesel engine exhaust exposure.

Generally, employers must take all reasonable measures to keep workplace exposures to carcinogens to a minimum. Employees who may encounter confirmed carcinogens should be properly equipped to eliminate all exposure to the carcinogen or, if not reasonably practicable, to reduce it to the fullest extent possible. The quantity and composition of diesel engine exhaust emissions vary depending on the type of engine, the composition of the fuel and many other factors such as the use of a catalytic converter.

Ask THEM about developing a sampling strategy to assess occupational exposures to diesel engine exhaust in your workplace.

Call and speak to the experts.

Since diesel engine exhaust is such a complex mixture of chemicals, employers should consider engaging a qualified person (QP) such as a Certified Industrial Hygienist (CIH) or a Registered Occupational Hygienist (ROH). These QPs, including consultants with the above-mentioned designations, will help anticipate, recognize, evaluate and control workplace exposures to diesel engine exhaust. They have the expertise and experience to develop an effective sampling strategy for workplace assessment and recommend measures to control workplace exposures. Contact us for more details and a free phone consultation to get started.

More specifically, a QP will consider the following steps during an assessment:

1 . Development of an exposure assessment strategy: This includes choosing the right decision criteria for acceptable exposures. This could be OELs, DNELs or occupational exposure bands depending on the evaluated chemical.
2 . Basic Characterization:  The QP will gather information to characterize the workplace, workforce and environmental agents. This is where the assistance from the employer will be key.
3 . Exposure Assessment: assess exposure in the workplace by grouping workers into similar exposure groups (SEGs) and evaluating all applicable exposure routes (dermal, inhalation, ingestion).
4 . Prioritization: prioritize exposure monitoring or collection of more information based on health effects and exposure risk
5 . Implement prioritized control strategies for unacceptable exposures using the hierarchy of controls
6 . Verification: Reassess to verify that acceptable exposures remain acceptable.
7 . Documentation: Communicate and document results.

 Diagram credit: S. Jahn, W. Bullock, J. Ignacio, A Strategy for Assessing and Managing Occupational Exposures , 4th edition, AIHA, p. ix  (2015)

Diagram credit: S. Jahn, W. Bullock, J. Ignacio, A Strategy for Assessing and Managing Occupational Exposures , 4th edition, AIHA, p. ix  (2015)


[1] https://www.carexcanada.ca/en/diesel_engine_exhaust/#diesel_fuel_use_in_canada

[2] Health Canada, Priority Substances List Assessment Report (CEPA) 2000: Respirable Particulate Matter Less Than or Equal to 10µm (2000)


[3] International Agency for Research on Cancer (IARC), Press Release No. 213  IARC: Diesel Engine Exhaust Carcinogenic, (June 2012)

[4] International Agency for Research on Cancer (IARC), Diesel and Gasoline Engine Exhausts and Some Nitroarenes, Vol 105 (2014)

[5]  Diagram credit: S. Jahn, W. Bullock, J. Ignacio, A Strategy for Assessing and Managing Occupational Exposures , 4th edition, AIHA, p. ix  (2015)

Risks associated with antineoplastic agents.

July 16, 2018
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With chemotherapy as one of the main cancer treatments, there is a global increase in the use of antineoplastic agents. Antineoplastic drugs, also known as cytotoxic drugs, are most often used in chemotherapy to treat cancer.   While they are used to treat cancer patients, they can be hazardous to healthy workers in health care, pharmacy, veterinary clinics and cleaning staff.   They have a toxic effect on cells within the body and there is no safe level of exposure to these cancer-causing agents. As a result, there is a need to implement rigorous health and safety practices with regard to these drugs. The OHS concerns are as follows:

  • Many antineoplastic drugs are carcinogenic;
  • Chronic issues can show up many years later;
  • Acute reactions can include skin irritation, eye and mucous membrane irritation, nausea, vomiting, hair loss and rashes;
  • Issues can include damage to the liver, kidney, lung and heart;
  • These drugs can affect fetal development.

Workers who may be exposed to cytotoxic drugs have to be aware of all of these risks, receive relevant training, use the engineering controls provided and wear all necessary personal protective equipment (PPE) to protect themselves. There are many exposure routes to take into account:

  • Skin absorption (direct contact with the drug or indirect contact with contaminated surfaces, clothing or handling patient excreta);
  • Inhalation (breathing in drug vapours or dust);
  • Accidental injection (needles or other sharps that puncture the skin); and
  • Ingestion (eating, drinking or smoking with unwashed hands or hand to mouth touching).

OHS Program basics.

Working with cytotoxic drugs requires strict policies and procedures. Every employer using cytotoxic drugs in their facility should at least consider the basics such as outlined below.

The right equipment. Engineering controls may be required including primary containment such as Biological Safety Cabinets or Isolator Cabinets and secondary containment for pharmacy dispensing and needle safety devices to prevent needle sticks.  The PPE needs to be easily accessible and workers need to be trained on how to properly use the equipment as well.

Training and good communication about the types of hazards workers may encounter is also very important.  Administrative controls such as worker training on hazards of chemotherapy drugs, proper use of engineering controls and standard operating procedures have to start from the very beginning with a comprehensive orientation and it has to include everybody, from shipping and receiving to front-line workers and managers.  Furthermore, workers need to receive training in all of the emergency response procedures for the variety of scenarios that could occur. Both the training program and the Occupational Health and Safety Control program should clearly identify the emergency procedures to follow in case of accidental exposure to cytotoxic drugs and/or in a spill response operation.

Monitoring and professional oversight are key to bringing all of the above elements together in a meaningful way. Employers should establish a comprehensive Occupational Health and Safety Control program, encompassing all of the aforementioned aspects, to protect both the workers and reduce their business risks. Occupational Health and Safety professionals recommend conducting exposure monitoring on a regular basis to ensure workers are not exposed and work surfaces are not contaminated. Ideally, an employer should involve a Certified Industrial Hygienist (CIH) or Registered Occupational Hygienist (ROH) to assess and develop a comprehensive program to minimize the possibility of missing a potential hazard.

About THEM

Since 1979, T. Harris Environmental Management (THEM) is committed to understanding and providing our clients in the institutional, commercial and industrial (ICI) sectors, with a variety of environmental and occupational health and safety solutions to their concerns. We meet our client’s needs by informing them of their options, reducing riskanxiety, and formulating qualitative, practical, efficient, and cost-effective solutions.  Services include the following highlights:

  • Risk Assessments
  • Environmental Health and Safety Program and Policy Development
  • Occupational Exposure Evaluations & Management
  • Safety Training Sessions

The team members at THEM have over 30 of experience and certified expertise in managing OHS services for the pharmaceutical industry and for hospital environments. Ask THEM for a professional consultation.


Silliker, A. , 2018,  “Workers exposed to chemotherapy drugs at increased risk for cancer, organ damage, reproductive issues”, Canadian Occupational Safety Magazine, 06/05/2018, Accessed: 16/07/2018, website: http://www.cos-mag.com/occupational-hygiene/36966-workers-exposed-to-chemotherapy-drugs-at-increased-risk-for-cancer-organ-damage-reproductive-issues/

Steege A.L., James M. Boiano, 2014, “NIOSH Health and Safety Practices Survey of Healthcare Workers: Training and Awareness of Employer Safety Procedures”, 57(6) · American Journal of Industrial Medicine, June 2014 with 74

Silica in Construction: Hazards & Control Measures

July 13, 2018
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In recent years, to protect workers in the construction industry against exposure to hazardous chemicals, the Ministry of Labour removed the exemption to Ontario Regulation 833 that construction projects enjoyed.  This regulation sets out requirements for protecting workers against chemical exposures and to abide by the current Ontario legal limit for respirable crystalline silica (quartz & tripoli) of 0.10 mg /m3 TWA.

Silica is very common in construction. It is a major component of sand, cement, gravel, stone, brick and mortar.   It can be present in asphalts, roof coverings, joint compounds, plaster, caulking compounds and mastics.  It is a common filler for paint, plastics, rubber and water filtration and employed in sandblasting, grinding, abrasives and scouring cleansers.

As a result, occupational exposure to crystalline silica is one of the common occupational hazards on a construction site. Health effects that result from overexposure to crystalline silica include breathing difficulty, lung irritation, decreased pulmonary function, progressive respiratory symptoms, and silicosis lung disease and/or lung cancer.

Silica Risk Factors in Construction

According to IRSST Report R-771[1], workers in construction face a serious risk of overexposure to crystalline silica.   Some of the dangerous occupations include pipeline labourers, drillers, bricklayer – mason, cement finishers and underground workers (IRSST Figure1 [3]).   For these occupations, the geometric mean silica exposures exceed the Quebec and Ontario respirable silica legal occupational exposure limits (OEL) of 0.10 mg/m3 TWA.

Occupation is not the only factor that needs to be considered when evaluating the risk of silica exposure – tools, tasks and working materials should play an important part in assessing this risk. Some construction tasks expose workers to silica in amounts, which are 1 – 16 times the acceptable legal limit (IRSST Figure 2 [3]). These tasks include silica for traffic control, tuck point grinding, sawing roofing, tunnel boring, breaking masonry, bush-hammering concrete, grinding and sawing masonry and abrasive blasting.

Some materials present higher exposures than others do with ceramic materials providing higher exposures than cement, followed by mortar and brick then by concrete blocks (IRSST Figure 3 [3]).

Finally, IRRST looked at silica exposure by tool and observed that all examples except for the sander exceeded the OEL for quartz silica in an 8-hour day.  These tools in increasing order of exposure included masonry tools, tuck point grinder, surface finishing grinder, tile cutter, drilling machine, jackhammer, tunnelling machine, bush hammer and portable masonry saw (IRSST Figure 4 [3]).

Control Measures

After reviewing all the aspects, which affect silica exposure in construction, it is imperative that engineering controls are implemented to protect workers.  Built-in exhaust ventilation and water spraying are important and absolutely necessary engineering control measures to minimize worker exposure to silica dust.

Administrative controls such as safe work procedures, worker training, on-the-job training, new worker orientation, safety meetings, hazard assessments, workplace inspections, silica awareness training and regular toolbox safety meetings are necessary to reinforce safe working with silica.

The final control in the hierarchy of controls is personal protective equipment. Respiratory protection may include full-face air-purifying respirators,  powered air purifying respirators or abrasive blast type CE supplied-air respirators depending on the type work being performed.   Equally important is that the construction project has a respiratory protection program that meets or exceeds the requirements of CSA Standard Z94.4- 2011 (reaffirmed 2016) selection use and care of respirators to ensure workers are trained, fit tested and work safely with the personal protection that is provided.

What can employees do to limit their exposure to crystalline silica?

Ontario Regulation 833 s. 3 (1) requires that every employer shall take all measures reasonably necessary in the circumstances to protect workers from exposure to a hazardous biological or chemical agent because of the storage, handling, processing or use of such agent in the workplace.   An assessment of worker occupational exposures is highly recommended.   Where exposure is possible then a control program to limit worker exposure should be developed.  The control program should follow the hierarchy of controls to minimize worker exposure.   The control measures in decreasing order of effectiveness range from elimination/substitution to use of engineering controls, followed by administrative controls and finally the use or respiratory protection.

Hierarchy of Controls [2]

Engineering controls could include dust suppression techniques such as using tools with water spray, negative pressure containment, and shower facilities with dirty/clean change rooms, wash stations.  Administrative controls could include silica hazard training, respiratory protection training, signage,  personal hygiene requirements and restrictions on eating drinking and smoking while personal protective equipment might include respiratory protection, eye protection and work clothes/street clothes change out.

Worker Safety with Silica: Key Questions to ask.

  • Is there crystalline silica in your work site?
  • Have you done everything to protect your workers from this hazardous substance
  • Are your workers trained on the hazards of crystalline silica?
  • Have all possible control measures been implemented?
  • Do you need air monitoring to ensure safety

T. Harris Environmental Management (THEM) can help you assess workplace exposures, develop a silica control program, provide training and assess respiratory protection requirements. Contact THEM – your silica experts.




[1] Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), Chemical Substances and Biological Agents,  Studies and Research Projects Report R-771 – Construction Workers’ Exposure to Crystalline Silica Literature Review and Analysis, 2013

[2] OSHA,  Alliance Program Construction Roundtable, Electronic Library Construction Occupational Safety and Health (elcosh), 2015, website:http://elcosh.org/document/4176/d001466/osha-alliance-program-construction-roundtable%3A-design-for-construction-safety-participant-guide.html, accessed 13/07/2018

[3] Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), Chemical Substances and Biological Agents,  Studies and Research Projects Report R-771 – Construction Workers’ Exposure to Crystalline Silica Literature Review and Analysis, 2013; Figure 1 – page 15, Figure 2-  page 17, Figure 3 – page 18, Figure 4 – page 18

Keeping Your Cool: Best Practices For Working Safely Under Extreme Temperatures

June 05, 2018
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Nice weather has finally arrived and many workers are feeling the heat. It is now the season to expect heat-related illnesses in the workplace. Summer may put many workers at risk of heat stress and seriously injure them. A series of hot and humid days following one another may adversely affect workers who did not previously acclimatize to heat exposure.   Extreme heat directly affects the health of workers, puts their safety at risk with impaired judgment and reduces productivity. This is a significant issue not only for occupational health and safety of people but also for the effectiveness of an organization as a whole. While Heat Stress Prevention Plans are complex and their development is better left to the professionals, every responsible supervisor should know some key facts to manage work in extreme heat on a daily basis.

Did you know?
Loss of consciousness because of heat stroke is classified as a critical injury and is a reportable event under the Occupational Health and Safety Act.  

Who is most susceptible to heat stress?

Fortune examined the sectors with the highest risk of heat stress and found that the sectors highest on the list were those with a lot of outdoor work. The top three are workers in government services, agriculture, followed by construction and business service. Government services included workers who maintained parks, fought forest fires and collected trash. Other professions who are inclined to suffer seasonally from this hazard include military personnel, landscapers and hazardous materials abatement contractors. Employers should also look out for new workers on the job. New unacclimatized employees working in manual occupations and ‘young workers’ who may not realize the risks are most vulnerable to extreme heat.

Important note:
There is a range of heat illnesses and they can affect anyone, regardless of age or physical condition.

What contributes to heat-related illness and how to mitigate the hazard?

Environmental factors such as high temperature, high humidity, and radiant heat sources such as direct sunlight, ovens, boilers, steam pipes and engines can contribute to heat stress.  The best way to remedy this is to make the work environment cooler through engineering control measures such as convection, radiant or evaporative heat control measures.

Did you know?
Just 30 minutes of exposure at the temperature of 40 C is enough to cause permanent disability or brain damage.

Administrative controls such as limiting exposure times or temperature, reducing metabolic heat load, enhancing tolerance to heat, screening for heat intolerance, health and safety training and instituting a heat alert or hot weather program are suggested.  Equally important are ensuring personal hydration, acclimatization of employees, controlling work duration times and monitoring the levels of physical exertion as key components of combatting heat-related illnesses. It is considered the next best method to protect workers because it allows employers to proceed with work without eliminating the source of the danger.

Conjointly with administrative controls, Personal Protective Equipment must be reviewed. PPE and protective clothing is the third level of protection from heat stress. Selecting the proper PPE for each situation can dramatically lower the effects of heat – and it is not the only reason to review all PPE use. In hot conditions, PPE that protects workers from other hazards may become uncomfortable and workers may then avoid wearing it. This is an issue that consultants frequently encounter when conducting inspections on job sites. For example, abatement contractors working in enclosures may avoid wearing a full-face air-purifying respirator in hot conditions where a powered air-purifying respirator that provides airflow across the face will be more comfortable.   The impermeable clothing required for abatement work prevents heat exchange from the body to the environment and contributes to heat burden.   Auxiliary body cooling may be required in the form of water-cooled or air-cooled garments or cooling vests.

There is no standard set of measures to prevent heat-related illnesses, so the best solution to comply with regulations and keep workers safe is to establish a Heat Stress Prevention Plan unique to each project or workplace (Ask THEM for assistance). Many physical factors affect the solutions that will be implemented: the age of workers, their state of health and physical fitness, required work tasks and personal protective equipment, as well as available resources – all play a role in finding the right solution. While each situation is unique, all plans share these common elements:

  • Methods to monitor temperature and humidity levels.
  • Description of conditions when heat stress measures should be implemented.
  • Outline of engineering controls and administrative controls.
  • Outline of proper PPE/clothing.
  • Emergency response measures.
  • Training requirements for all workers and supervisors that include the signs, symptoms and prevention of heat stress and how to deal with those risks.

Heat Stress in Indoor Environments

Although heat stress is typically associated with seasonal outdoor work environments, heat can be a year-round hazard in indoor workplaces. Commercial bakeries, kitchens, laundries and environmental abatement sites are just some activities that may be affected. In these workplaces, workers are often near sources of radiant heat or inside buildings with limited cooling capabilities and air movement.

Common question:
Should an individual in an indoor work setting use the same preventive measures for heat stress as someone working in an outdoor setting?

Measures to prevent heat-related illness are similar in both indoor and outdoor environments, but indoor workplaces have additional concerns.  For example, an indoor environment with little airflow may diminish the cooling effects of that sweat provides through evaporation. Nonetheless,  these environments also provide additional opportunities to use engineering control measures.  As with outdoor work environments, it is important to develop a prevention plan to handle the potentially hazardous indoor heat.

About THEM

T. Harris Environmental Management Inc. is experienced in assessing workplace factors that may contribute to heat stress/heat strain are able to provide recommendations on engineering and administrative controls. We can help conduct a detailed analysis of work areas regarding clothing properties, worker demands, task times and thermal environment according to the ACGIH threshold limit value as recommended by the Ontario Ministry of Labour. We can help you determine if excessive heat strain is occurring and whether general controls or job-specific heat stress/heat strain controls are required in your workplace.   Please call us to conduct an assessment.