National Pollutant Release Inventory (NPRI): What is it?

February 28, 2018
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The National Pollutant Release Inventory (NPRI) is Canada’s legislated, publicly accessible inventory designed to track and catalogue the release of pollutants, their disposal, or their transfer to recycling facilities. Every year on June 1st, facilities nationwide are subject to compile information on the following pollutants: air contaminants, pollutants released in water, and waste products disposed on land. The NPRI oversees the usage of over 300 unique substances Canada-wide and over 7000 facilities were included in the registry last year alone.

Do you need to register?

Facilities in every province and territory across Canada are responsible for registering with the NPRI if they meet certain conditions, such as:

  • If one (or more) designated NPRI substance is manufactured, processed, or otherwise used at the facility during the year.
  • If the total working hours accumulated within the facility is greater than 20,000 hours. This is equivalent to approximately 10 full time workers over the calendar year.

If a facility you own or manage has these conditions, you must register in accordance with Federal Law. Additionally, facilities involved in incineration, wood preservation, terminal operations (among others) must adhere to the NPRI reporting requirements regardless of employee hours worked.

If you have any doubts about whether or not your facility qualifies as one that requires registration, contact a professional. Industry professionals have in-depth knowledge of the NPRI database and the over 300 substances that it encompasses.

Unsure if you require registration? Contact THEM to find out.

The Importance Of Filling The NPRI With a Professional

Environmental consulting professionals possess a vast knowledge of the NPRI reporting requirements and can streamline the reporting process to ensure it is handled in a quick and orderly fashion. For instance, facilities may be required to report based on Concentration Threshold, Mass Threshold, Employee Threshold, and Activities/Sector. The reporting criteria are different for each section. Failure to meet the reporting requirements or reporting deadline may result in fines and penalties.

Environmental specialists follow a number of steps to ensure all issues are dealt with in a timely fashion. A brief overview of the steps taken include:

  1. Determining the substances that a facility uses that may fall under the NPRI catalogue.
  2. Verifying the total quantities of substances a facility manufactures, processes, or otherwise uses in a calendar year.
  3. Establishes whether the use of these substances surpasses the NPRI reporting threshold.
  4. Ensures the appropriate reporting procedure is followed for all substances over the threshold.


Contact Us for a Complimentary Consultation to Get Started


10 ways to keep renovation projects safe

February 28, 2018
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It is not easy to predict when the weather will get warmer, but one thing that is certain to occur: with the rise in temperatures each year, comes the renovation season! Winters are, in general, unbearably rough when it comes to renovating a building or an open landscape. They lead to losses in productivity and often to the occurrences of various types of injury. In most cases, project managers and planners cluster renovation projects around warmer temperatures. Does a higher number in the thermostat instantly mean safer work conditions for on-site workers and a reduced number of workplace injuries? It is not always the case.

Nonetheless, the answer to the above is affirmative if renovation managers execute projects with the proper planning and precautions. The following is a list of items to be considered to keep renovation projects safe and most importantly, to exercise due diligence in trying to prevent accidents from happening.


Before project start:

Plan well – The best way to control renovation risks is to recognize well in advance the various types of hazard present in the work areas and include specialists, such as environmental consultants, who can assess risks and recommend effective mitigation strategies in areas where your knowledge is incomplete. Good project management, such as effective scheduling of work, can prevent rushing through renovation activities, decreasing employment turnover rates, workplace injuries and runaway vendor costs. Understanding the potential issues that can arise on a project and at least talking with a consultant to see if external assistance is necessary is a good way to avoid costly surprises, stop work orders and other project liabilities.

Understand the applicable safety guidelines and regulations – Knowledge of guidelines and regulations is key to ensure safety for all pertinent personnel and reduce potential liabilities. These regulations govern requirements for air quality, asbestos, lead, drinking water quality, fall protection, ladder safety and other aspects of construction. While they are available from many online sources, these regulations can be complex and it is prudent to engage a consultant if you have any doubts in their application.

Provide training –To work around unsafe chemicals and to minimize the event of an injury, workers have to be competent. A competent worker, defined under the OSHA [1], is a person that possesses knowledge, training and experience to perform the work; is familiar with the Act; and has knowledge of all potential or actual danger to health and safety in the work. That is why training is mandatory for all workers performing renovation activities as well as personnel with supervisory roles. Thus it is the worker`s duty to attend training sessions and it is the responsibility of supervisors to ensure they are provided.

Set up good housekeeping –Establish designated areas for equipment storage, lunch breaks, and other special activities such as welding, drilling and cutting. Having these areas set up correctly will serve as a means to prevent worker exposure to toxic substances and will minimize the possibility of tools from falling from heights or obstructing the view of an easily identifiable fire hazard.


Know the materials present onsite – Understand all of the materials on site and determine which types are hazardous as described under different government acts. One of the ways of achieving this is by ensuring that SDS documentation is present for all chemicals. Additionally, materials may contain substances referred to as Designated Substances. When handling or disturbing them, renovators are obligated to follow specific procedures and guidelines. It is a good practice to identify these materials, figure out the types of contaminants present, and determine their respective health concerns. Consultants are available to assess risks and conduct sampling of such substances, as required before any renovation work.

Be aware of exposure limits for all hazards present– The outcomes of overexposure to hazardous substances are not always noticeable immediately. They may be long-term and go unnoticed for years. To avoid threatening consequences for both workers and employers in the long run, it is important to ensure safe work conditions with your existing exposure amounts. If exposure exceeds pre-set limits, employers should ensure that workers follow the correct measures to avoid serious health effects.

Awareness of heat stress – Some industrial plant renovations involve the contractors working in hot environments, around steam pipes and/or hot water lines. Heat sources can present serious hazards and discomforts to workers, causing illnesses such as heat exhaustion and heat stroke. An Assessment of Heat Stress/Strain would help prevent health hazards in this environment.

Constant monitoring of workspace – Determine if your work environment is safe for entry and for the performance of renovation activities. Certain environments are mandated to be constantly monitored because the level of toxic chemicals may change during the work processes. An example of these environments is the inside of a boiler, classified as a confined space under OHSA, due to atmospheric hazards and the potential event where oxygen level falls below the acceptable range.

During renovations activity:

Consider ergonomics – A healthy individual shows better productivity and performance at work [3]. Ergonomics in a renovation sites is a serious consideration: it includes the use of mechanical lifting, less carrying, use of of ergonomically designed tools to reduce awkward postures, adequate break times, warm clothing, etc. Therefore, it is important to consider ergonomics when managing a renovation project. Even healthy employees are prone to ergonomic injuries.

Use appropriate Personal Protective Equipment (PPE) – personnel would be deterred from renovation activities if they feel that the appropriate PPE were not provided. Project managers must analyze carefully the scope of work and determine the appropriate PPE specific to the work. PPE must only be selected in accordance with the various CSA requirements [2]. For example, respirator fit testing helps ensure that workers are not breathing in unsafe substances.

Although there is a great number of safety and health related concerns in a renovation site,There are even greater ways to keep the same work environment safe. This list was provided for reference, to interested project managers and planners who are considering a renovation project for their sites. It is always important to start planning your projects with safety in mind. If in doubt, consult industry experts regarding any of the above-mentioned items. T. Harris Environmental Management(THEM) personnel have extensive knowledge and training when dealing with renovation projects, and always make themselves available to their valuede clients.  THEM`s technical expertise helps industry leaders successfully and safely renovate on their sites, specializes in providing hazardous materials management, corporate training, environmental site assessments, indoor air quality assessments, and much more.

For a more detailed list of services, contact a representative.



[1] Morrison, K. W. (2012, July 1). What is a ‘competent person’? Retrieved February 15, 2018, from http://www.safetyandhealthmagazine.com/articles/what-is-a-competent-person-2

[2] Personal Protective Equipment (PPE) Retrieved February 15, 2018, from https://www.ihsa.ca/topics_hazards/ppe.aspx

[3] Ergonomics Retrieved February 15, 2018, from https://www.worksafebc.com/en/health-safety/hazards-exposures/ergonomics

Mind the Gap: Recognizing women’s unique OHS needs.

February 28, 2018
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Today, women are becoming more numerous in the global workforce and are moving into traditionally male-dominated industries. A half a decade ago, industries like construction, property management, maintenance and production management could not boast of many female employees. Today, even though women’s representation in many of these industries is still under 10 percent, the number is rapidly growing.   For employers who want to recruit and retain staff, building an inclusive workplace culture that supports employees across differences in race, class, and gender is crucial to success. The knowledge and skills to do this are frequently missing in many work environments.

This poses a range of gender-related questions about the different effects of work-related risks on men and women. For example, women have different exposure limits and protections when it comes to hazardous substances, biological agents, the physical demands of heavy work and ergonomic design. Occupational health and safety regulations have traditionally focused on dangerous jobs in sectors dominated by male workers. As a result, OSH standards and exposure limits to hazardous substances are often based on male populations and laboratory tests. The risks to men workers are better known and addressed and OSH hazards affecting women have been traditionally under-estimated. These factors can affect the bottom line by lowering retention rates, reducing morale and increased absenteeism. There are also the direct and indirect costs of complaint investigations that must be considered. Below we outline just some of the issues that can be beneficial to address and to improve women’s well-being in the workplace.


Women in non-traditional employment frequently face health and safety risks due to the equipment and clothing provided to them at their workplace. Personal protective equipment (PPE) and clothing (PPC) are often designed for average-sized men. This poses both health hazards as the protective function of PPE/PPC may be reduced when they do not fit female workers properly. For example, poorly fitting respirators may not protect adequately against chemicals, loose clothing can be caught in machinery or overly large boots can cause tripping. Furthermore, many women may find the poorly fitting equipment uncomfortable and put themselves at risk by refusing to wear it.

In recent years, many manufacturers have been making PPE that fit women, but it is rare and expensive. Many employers do not make the right PPE available for women and are resistant to women bringing their own PPE. Providing PPE in a wide range of sizes would benefit both workers and employers.


Researchers and employers find that women have gender-specific musculoskeletal problems. For example, their shorter hands and lower grip strength as compared to men frequently make standard hand tools too large. In addition, many women may have less upper body strength than men, which leads to back problems when lifting heavy objects. As a solution, making tools available in smaller sizes to accommodate women and adapting lifting demands for women as well as men across your business can help. Being aware of similar issues and addressing them is an important step to an inclusive workplace.


Workplace exposures to hazardous substances can play a role in the development of cervical and breast cancer. NIOSH is conducting studies of women exposed to the following hazardous substances to determine whether there is a link to cancers: Ethylene oxide and Perchloroethylene. These chemicals are widely used in industries where women are the dominant workforce.

Reproductive Hazards and Chemical Exposure:

The effects of potential occupational hazards on women’s reproductive health have increased in recent years as more environmental hazards are identified and as more women enter the paid workforce.  A range of occupational reproductive hazards has been documented but a large number of possible risks still require further examination.

Solvent levels that are considered safe for adults may affect IQ of the fetus. The unborn child’s brain is much more sensitive than the adult brain. According to research, children born to mothers exposed to solvents in the workplace appear to have significant developmental problems such as lower IQs, compromised language and memory skills, inattentiveness and hyperactivity. This information suggests that current workplace exposure limits may not be good enough and employers should do everything possible to help women minimize such exposures. Women with occupational exposure to toxic chemicals are in general highly vulnerable to adverse reproductive health outcomes. Medical experts warn that there is sufficiently robust evidence to support that exposure to chemicals during pregnancy leads to adverse reproductive and developmental health outcomes. And the risks are highest for those exposed at work.

The issue is not solely about women and pregnancy. Father’s exposures are also relevant. Prenatal exposure to certain chemicals has been documented to increase the risk of cancer in childhood. For example, adult male exposure to pesticides is linked to altered semen quality, sterility, and prostate cancer. Postnatal exposure to some pesticides can interfere with all developmental stages of reproductive function in adult females.

Chemical exposures are not the only concerns. Factors that have a cumulative effect on risk include working night hours, irregular or shiftwork schedule, standing, lifting loads, noise, and high psychological demand coupled with low social support . The researchers say eliminating these factors before the 24th week of pregnancy can bring the odds of impairment down to those of unexposed women.  Exposure to a range of workplace risks in pregnancy can increase the likelihood of having an under-sized infant, according to a new report in the American Journal of Public Health. Additionally, working night shifts in the first three months was linked to a doubling of a woman’s risk of early labour.

Employers should improve recognition of women’s reproductive health in workplace policy and processes. This is necessary to both provide assurances to women that women can discuss their needs with employers and to provide managers and employers with tools to support them. We encourage employers to review policies and processes around occupational health and safety to ensure that these health conditions are taken into account. In particular, employers should ensure that occupational health practitioners recognise women’s reproductive issues during risk assessments.


Richard Nelligan: Celebrating a Career of Success and Dedication.

January 29, 2018
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We are at once delighted and disheartened to announce that Mr. Richard Nelligan, Vice President – Eastern Canada, will be retiring as of January 31, 2018. Richard has been a consummate professional and we truly appreciate his dedication and commitment to making THEM Ottawa in particular, and THEM as a whole a better company. Many successful projects that we recognize as the backbone for T. Harris Environmental Management (THEM) were a reflection of his recognized expertise and experience in large-scale private, historical and government sensitive projects.  He has been involved with some of the largest, most diverse and complex projects in Canada.  Richard has been a tremendous part of our team by sharing this knowledge with all his fellow team members. In addition to his high level of competence and skill, he has achieved great camaraderie with his rare sense of humour.

Richard has provided THEM with over 30 years of devoted service and we treasure his commitment. His industry knowledge and his wide range of expertise have been invaluable. In his projects, he demonstrated expertise in all aspects of asbestos technology, consulting and environmental hazard abatement. His track record of success with large hazardous materials abatement projects and in consulting for a variety of ICI clients underlines his extraordinary professionalism.

Throughout his career, Richard has contributed to every aspect of the industry from policy development to building relationships with clients. He liaised with private clients and government agencies regarding hazard assessments and recommendations on abatement projects. He was involved in every work aspect of environmental consulting services for large-scale construction projects including hazardous materials survey reports, budget estimates, hazmat abatement tender documents and drawings, submittals reviews, inspection, monitoring, progress payments and contract administration.

Richard’s retirement is our loss, but a well-deserved new beginning for him. We wish Mr. Nelligan well as he sets off to enjoy his retirement.

The growth and development of the entire THEM organization is the ultimate goal. Chris Nielsen has been named as Richard Nelligan`s successor in the role of Vice President-Eastern Canada. Chris has been working closely with Richard and he is now excited to continue his efforts with THEM in an expanded role. Chris is committed to furthering our opportunities in Ottawa as well as continuing to support other offices with their environmental challenges and opportunities.


Don’t Hold Your Breath: Managing IAQ in the Hospitality Industry

January 23, 2018
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As hotels rush to accommodate the health and environmental concerns of their patrons, they cannot ignore the rising universal concern with indoor air quality (IAQ). As healthy living is the new trend, travellers are paying more and more attention to IAQ-related health concerns and the benefits of clean air. According to a study by the International Hotel and Restaurant Association, more than two-thirds of frequent travellers are concerned about air quality. Sixty percent indicated that they had suffered poor sleep, runny or stuffy nose, sneezing, headache, cough or sore throat because of staying in a hotel room with poor indoor air quality.

Poor air quality in hotels is a service, financial and marketing issue. Consider people with respiratory problems. The American Lung Association estimates that 3 out of 5 people suffer from respiratory difficulties. This translates into an average of one person per family. Often travellers will not complain about a poor environment or a room that aggravates their allergies, but these guests will not return and will not recommend it to others. Their symptoms are a direct result of poor indoor air quality. The typical symptoms that travellers experience are sore throats, headaches, running nose and itchy eyes. Given that many of us spend up to 90% of our time indoors, this is an important issue.

Contact a professional to evaluate your IAQ


Reasons to monitor your IAQ:

  • The obligation to ensure you are not creating a risk to public health. The mere mention of the word “contamination” is scary for most people involved in commercial building management. This is a reasonable reaction, because while contaminant outbreaks carry the possibility of deadly consequences.
  • Improving guest satisfaction. For general health, well-being and safety reasons, customers require good indoor air quality and environment.
  • Upholding staff productivity. Guests are not the only occupants likely to suffer health effects – staff spend their working hours in the same environment. They cannot work efficiently and effectively if they are uncomfortable. With poor indoor air quality, employers may face high health insurance and workers’ compensation costs as well as low worker productivity and frequent absenteeism. Healthier buildings can boost employee productivity by approximately 15%(Bergs, 2018)
  • Reduce operating costs (and carbon dioxide emissions) through lower energy consumption with proper humidity and maintenance.
  • Increase revenues. Customers who are satisfied with indoor air quality and comfort of their hotels are likely to return.

Start Monitoring Your IAQ Today


Issues that can have an adverse effect on your IAQ:

  • Poor ventilation as a result of energy efficiency measures
  • Off-gassing VOCs from building materials
  • Water damage which may lead to mould growth
  • Chemical contaminants
  • Smoking guests
  • Poor air quality within indoor swimming pool areas


5 Ways to Improve Indoor Air Quality

Get your IAQ assessed by a professional.

If in-house efforts have not solved your indoor air quality concerns or if you want to verify that you are on the right track, you should contact a professional indoor air quality consultant. Even when you think you have found the source of the issue, verification may require specialized sampling methods, as well as professional experts to interpret the test results correctly and provide recommendations on how to rectify the issues. Engaging a consultant is especially important when indoor air quality concerns escalate. An independent investigation will develop a credible analysis and actionable recommendations that all stakeholders can trust. Contact a professional for a consultation.

Be aware of pollution in your air.

Although society tends to think of air pollution as an outdoor issue, indoor air can be worse. With an increased air tightness and other energy efficiency strategies, indoor air circulation is frequently restricted and pollutants remain trapped in your indoor environment. The way to improve this is to focus on ventilation. Strategies such as heat recovery can provide fresh air without the loss of heat. Regularly maintaining your HVAC systems and changing air filters is also key. To check if your efforts are providing sufficient results, routinely get your IAQ tested by a professional at least once per year.

Watch out for VOCs.

Do your research if you have any questions about what is going on your walls and into your renovations. Materials like carpeting, paint and vinyl can release harmful VOCs (volatile organic compounds). Check with manufacturers to find materials that minimize chemical off-gassing and use low-VOC paint for interior design.

Keep humidity between 20%-60%.

Mould can produce allergens and mycotoxins, which have adverse health effects. Health effects range from allergy-like reactions (even in non-allergic people) to asthma attacks. Long periods of low relative humidity can cause dryness of the skin and mucous membranes, which may lead to chapping and irritation. High humidity levels can result in condensation within the building structure and on the interior or exterior surfaces and subsequently lead to the development of fungal growth.

Clean with care.

Many everyday cleaners contain fragrances that make things smell ‘clean’, and these can aggravate respiratory problems.  With advances in chemical-free cleaning, it is possible to use HEPA vacuuming, steam and engineered water to reduce chemical use and thus avoid adverse effects on indoor air quality.

Contact a professional for a consultation

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Evict Radon With Professional Help.

January 23, 2018
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 4 Reasons For a Professional Radon Test

January is Radon Action Month. According to Health Canada, radon is the second leading cause of lung cancer and the only way to know if it is in your building is to test. While there is no current specific legal requirement to test for radon, more and more commercial tenants are employers and are requesting their spaces to be tested. Under the Occupational Health and Safety Act, it is the employer’s duty to keep their employees safe from occupational exposures. However, the only way for an employer to know if they are compliant with the Canadian Labour Congress (CLC) or the Naturally Occurring Radioactive Materials (NORM) Guidelines is to have their work environment tested. As a result, proactive property managers who have completed this testing are gaining market advantage. We see highly proactive property management firms completing radon assessments as a part of their BOMA Best applications.

When it comes to radon testing, there are short-term and long-term testing DIY kits available. Short-term tests only provide insight as to radon levels during the short time of testing, while long-term tests, allow you to track the levels of radon over an extended period. Short-term testing is prone to missing spikes in radon exposure, whereas long-term testing captures them. It may be prudent to use both types of testing kits, because many different variables affect radon levels, and they can fluctuate at different times of the year.

It is good to know the option is always there to test for radon gas on your own, but in most situations, including property management, it is probably better just to hire a C-NRPP-certified radon measurement professional. If you hire a professional, they will oversee the testing process and handle the samples appropriately as to exclude the possibility of compromising the integrity of the test.

Get Your Building Professionally Tested

Here are some of the advantages to hiring a radon professional:

1 . Ensures correct testing process and placement. Radon testing can be complicated. The results can be easily swayed by many different variables: preparation of the sampling media, sample collection, processing, packaging and transportation of samples when tests are completed. Accordingly, there are many ways it could go wrong at every stage from setup to time of analysis. Simple things like opening doors or windows, setting up the testing kit for a too short of a time or failing to seal the test kit well for shipment, can cause inaccurate results. C-NRPP certified professionals comply with recognized standards of practice to protect public health and safety.

2 . Unbiased third-party validation results. While most property managers are honest and hard-working professionals, they can still encounter challenges in gaining credibility with their tenants. A third-party licensed, professional test ensures that there is no question about the quality of results.

3 . Transfer of risk and assurance of legal compliance. Both the provincial and federal governments are considering laws to make radon testing mandatory. Using knowledgeable and licensed professionals ensures that you are protected from any errors and omissions.

4 . Actionable recommendations. Once you have the results from the lab, what are you to do with this knowledge? Unlike a test result, radon professionals are able to provide a property manager with a report containing actionable recommendations. This report will specify the scope of any remediation work, save you hours of research and the risk of making any mistakes.

Get Your Building Professionally Tested

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Meet the Expert: Mr. Chris Nielsen, B.Sc., P. Geo. (Limited), QPesa

January 23, 2018
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We are very pleased to announce that Mr. Chris Nielsen, B.Sc., P. Geo. (Limited), QPESA, is taking over the role of Vice President – Eastern Canada. 

Mr. Nielsen is a senior environmental consultant, geoscientist, project manager and leader with more than 30 years of progressive experience in environmental site assessment, remediation, hazardous materials management and health & safety consulting.  Chris has led environmental groups in two international corporations where he was responsible for day-to-day operations, budgeting, staff retention and mentoring and the overall business operations of the groups.  Mr. Nielsen has managed multiple large projects in a variety of client sectors and has strong expertise in client relations, project budgeting, scheduling, delivery and supporting systems development in residential, commercial, institutional, industrial and public sector settings.

In his work, he demonstrates subject-matter expertise and exhibits strong resource leadership among large projects, including a $2.5 million environmental site assessment on a former military base, asbestos surveys of 1,900 buildings throughout Ontario, a large site assessment and remediation project on the Niagara Escarpment, and many smaller projects involving mould, asbestos, lead and other Designated Substances as well as contaminated properties.

Chris is an active volunteer, mentoring new professional geoscientists through a program organized by the Association of Professional Geoscientists of Ontario, and is currently the President of Muskies Canada Sport Fishing & Research Inc., a not-for-profit volunteer conservation organization.


December 22, 2017

As companies innovate and redevelop products, a change in the manufacturing process or an introduction of a new process are becoming common occurrences.  These changes can involve the introduction of complex chemical mixtures. The use of complex chemical mixtures poses many safety challenges. Frequent questions include:

  • Can workers be overexposed by inhalation?
  • Is the mixture a flammability hazard?
  • How do I measure exposure?
  • Are engineering controls adequate?

For the best results, company should engage a safety professional to evaluate if a chemical mixture is safe to use.

Contact T. Harris Environmental Management for a consultation

The Story:

The client company, a small innovator in the food industry, has implemented new processes. When the executives suspected that their new production process was causing a possible overexposure issue, they looked for a niche expert in occupational hygiene. As a small producer in a competitive market, they had a small budget to spend and a tall order of expectations to meet.

The goal of the client company is to be a quality local alternative to imported items in their category. As a result, they were looking for a solution that would guarantee that their product and process remain safe for consumers and workers. As a part of the overall corporate strategy, ensuring occupational safety was more than just a legal precaution – it helped gain a competitive edge. Importers could not guarantee worker safety in their production facilities and did not provide insight into product safety. Overall, the company was aiming for a certified niche expert who could understand and ensure the safety of their operations. The solution had to be (1) cost-effective, yet (2) timely and (3) professional. The executives chose THEM as a reliable consultant with proven expertise and a history of success since 1979.

The Challenge:

This project required THEM to assess the potential occupational exposure to a paint primer.  A paint primer is a complex mixture of chemicals. Current assessment techniques and laws for chemicals tend to focus on potential exposure to individual chemicals, mostly considering only a single source. This practice is concerning, because, as a result, manufacturers rarely examine potential risks of these chemicals in combination. Although, scientists and regulators develop and apply methodologies for assessing the combination effects of chemicals, so far there is no systematic, consistent, comprehensive and integrated approach across different pieces of legislation.

Harris Environmental Management Inc. (THEM) are experts in advance sampling strategies and other exposure determinants to assess what is significant or important with respect to a chemical mixture in order facilitate professional judgement on assessing the safety of the mixture.

Contact T. Harris Environmental Management for a consultation

Evaluating Occupational Exposure to Paint Primer

Finding the Focus: Currently, in the production processes, the variety of chemicals and their possible combinations is so great that it neither realistic nor useful to test every combination. Where do we begin in assessing the complex mixture of paint primer?   The assessment begins with a qualitative step to prioritize exposures to minimize the need for the sampling.

A quick look at SDS: Looking at the manufacturer’s safety data sheet (SDS), consultants determined that this primer paint contains three main volatile solvent ingredients in the coating mixture: (83-93%) 1-methoxypropyl-2-acetate, (<4%) 2-methoxypropyl-1-acetate and (2-7%) ethanol.  The remaining ingredients are proprietary polymers with no vapour pressure according to the SDS. They do not contribute to the volatile organic compounds and can be left out of the vapour pressure analysis of the mixture.

Further analysis/modelling: Using the AIHA[1] fundamental heuristics of Rule-of-Ten (ROT) and Vapour Hazard Ratio (VHR) the consultant can assess complex solvent mixtures.

The Rule-of-Ten correlates the fraction of saturated vapour pressure with the level of control.   The fraction of saturation is an approximation of the 95th percentile  and should not be considered an absolute exposure level but rather be used as a tool to provide the correct order of magnitude of exposure.

Vapour Hazard Ratio (VHR) is an indication of the potential of the agent to exceed acceptable airborne levels. The American Industrial Hygiene Association have linked VHR to the required level of ventilation control necessary to maintain the 95th percentile exposure below the agent’s occupational exposure limit to assure worker exposures are acceptable.   The significance of exposure is related to both tendency for a material to vapourize and levels of concentration in the air that can cause harmful effects.

Table 1.Vapour Hazard Ratio Linked to Ventilation

Table 1 associates ranges in VHR with the required level of ventilation control necessary to assure worker exposures are acceptable.

Finding the controlling component: Depending on partial pressures and concentration, the controlling compound with the highest adjusted VHR can be determined in a chemical mixture. If occupational exposure air monitoring shows that the controlling ingredient is below the occupational exposure limit, then all chemical ingredients will be in control. If such an ingredient is identified, it can drastically limit the need for multiple chemical air sampling and the site can focus on the only on the controlling compound.

Using Raoult’s Law for ideal solutions the consultant is able to calculate partial pressures for each chemical ingredient in the solvent mixture and then determine the adjusted vapour hazard ratios. With this method, consultants calculated that of the three volatile solvent ingredients present in the mixture, 1-methoxypropyl-2-acetate, also commonly known as propylene glycol methyl ether acetate, has the highest adjusted vapour hazard ratio of 0.062 and was the controlling component for occupational exposure monitoring.    This VHR corresponds to a Vapour Hazard Ratio Scale of 2 from Table 1, which indicates that good general ventilation between 6 – 12 air changes per hour is the required level of ventilation to control occupational exposure to this paint primer.

Determining the necessary ventilation control measures:  If we use the corrected vapour pressures for the ingredients to calculate the saturation vapour concentrations for each ingredient and multiply by the fraction of saturation value for each level of control from the Rule of Ten, we get the following relative risk determination based on ventilation control as per Table 2 below.


Table 2. Saturated Vapour Pressure Calculation & Relative Risk Determination By Ventilation Control Parameters (Rule-of-10)

These calculations showed that confined space ventilation conditions (very limited) are required before the three chemical ingredients exceed the occupational exposure limits.   Even under poor ventilation conditions (< 6 air changes per hour), occupational exposures to this solvent mixture would be acceptable.


Technical Outcomes:

1. THEM were able to demonstrate to the client that 1-methoxypropyl-2-acetate is the controlling solvent in this mixture. If air sampling is to be conducted, then this is the chemical ingredient that should be measured thus saving the client money on analytical costs for the other two chemical ingredients.

2. THEM showed that general good ventilation of 6 – 12 air changes per hour would control occupational exposures below the occupational exposure limit.

3. THEM found that concentrations in a confined space would not exceed the ethanol LEL of 3.3% (33,000 ppm) or of 1-methoxypropyl-2-acetate)  LEL of 1.3% (13,000 ppm) (78°C) and the paint primer is not an explosion hazard.







[1] S. Jahn, W. Bullock, J. Ignacio – A Strategy for Assessing and Managing Occupational Exposures – 4th Edition, American Industrial Hygiene Association, Chap. 26, p. 335-348, 2015

Meet the Expert: Richard Quenneville, B.Sc., CIH, ROH

December 22, 2017
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Richard Quenneville, B.Sc. (Chem.), is a Certified Industrial Hygienist (CIH) and a Registered Occupational Hygienist (ROH) with over 30 years of experience. He has been a successful external occupational hygiene consultant for the past 14 years. Currently, he is the Senior Director of Corporate Services for T. Harris Environmental Management Inc.  Before joining our company, most of his work was in telecommunications, manufacturing and pharmaceutical industries in both union and non-union environments. Richard has thrived in local, regional and international EHS positions for companies such as Nortel Networks and GlaxoSmithKline.

Richard is recognized for his excellent professional performance. He is a recipient of the OHAO Hugh Nelson Award for Excellence in Occupational Hygiene and past president for the Occupational Hygiene Association of Ontario. As an expert, he often speaks at conferences and takes an active role in developing industry best practices.

Richard has a broad base of professional knowledge. He is an expert in risk assessment, occupational exposure assessment strategies, exposure modeling and statistical analysis of sampling data.  He is also a subject matter specialist in asbestos, lead, silica, isocyanates, nanomaterials, welding, heat stress, legionella and many other assessment strategies  including dermal exposure and biological exposure monitoring.

Richard develops workplace strategies that are tailored to address only the hazards that you need to evaluate.  He can help your business with an occupational exposure sampling strategy that is concise and practical. With a combination of modeling and / or on-site sampling, his strategies will maximize the benefits of the evaluation relative to the costs and respect your budget. Richard can also deliver occupational health and safety training that directly meets your worker training requirements.

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The Smell Of The Holidays Is In The Air – 6 Tips to Keep It Fresh!

December 15, 2017
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Christmas Day is the most toxic day of the year to be at home. Families could breathe in as many harmful particles as if they stood all morning on a busy road in London, UK. People count on good building management to insure that that fumes from the ovens, fireplaces and party poppers are not the highlights of their holiday parties. So, what is a property manager to do?

  1. Keep the air flowing.

With all of the festive cooking and decorations, hazardous particles are bound to spread around your well-insulated building. They have the potential of giving your tenants and their guests flu-like symptoms and allergies. Electric stoves, for example, emit ultrafine particles smaller than 100 nanometres in size, studies show. They can get deep into our respiratory systems and cause inflammatory effects. Speak of bad timing to fall ill!

To prevent this, make sure your ventilation is set to deliver a sufficient amount of clean air from the great outdoors. According to a Survey on Minimum Ventilation Rate of Residential Buildings the most common Air Change, based on the sample set evaluated, was 0.5 air changes per hour. This means that half of the indoor air should be replaced by fresh air every hour, or in other words that all air should be replaced 12 times per day. This is for the health of both buildings and people.

holiday tree spreads mould

  1. Ditch the Mouldy Christmas Tree.

Researchers discovered that mould spore levels can increase up to five times the normal level within a two week span with the presence of a natural Christmas tree. No wonder many people tend to get the holiday “flu”. Mould sensitivity is a known cause of allergies and asthma attacks. To keep your tenants healthy, go for the artificial tree, or just ditch it altogether.

If you must have a natural Christmas tree in building, here is how to reduce its ill effects:

  • Clean the trunk with water and bleach.
  • Get rid of any surface particles before you bring it indoors.
  • Set the tree up later and dispose of it as soon as possible. Mould spores increase with time.

With tenants spending more time indoors, it is a good idea to do an overall Indoor Air Quality (IAQ) Test and step into the New Year with your building smelling fresh!

Contact us for an IAQ Assessment Today

  1. Leave Old Decorations in the Attic.

Vintage ornaments might be the most dangerous. When the dangers of asbestos were still undiscovered, its heat resistance made it perfect for Christmas tree decorations and sprinkles. The oldest decorations made in 1920s to 1970s, may still have small amounts of asbestos.

On a separate note, dust from insulation (i.e. vermiculite) in the attic or from hanging decorations can also contain asbestos. If your home is old and you have not tested for asbestos, be extra careful. The children in the home are most vulnerable when it comes to asbestos dust. They have a higher breathing rate and will inhale more of the fibers. Younger kids breathe in dust when they play on the floor or with the ornaments. If in doubt, leave the decorations in the attic, where the asbestos is better left undisturbed, and get asbestos tested soon.

  1. Stop Spraying Snow.

While asbestos is not an ingredient in modern snow sprays, they contain acetone or methylene chloride. Inhaling these chemicals can cause respiratory reactions, headaches and nausea. Longer or more concentrated exposures can be more serious. Both your tenants and your employees are safer without this stuff. If you are dead set on making snow happen, use proper PPE.

  1. Avoid Air Fresheners and Cut Out the Candles.

Lighting candles and spraying a festive air freshener are two simple ways people make their homes feel cozier during winter. Air fresheners produce airborne contaminants that irritate the respiratory system.

There is a dark side to candles too. Colour pigments can release metals when the candle burns and soot is produced when the candle flame flickers. These particles and soot have health impacts.

  1. Leave Lead Lights Alone.

Cornell researchers found that many Christmas light sets contain such elevated levels of lead, meaning that they exceed limits set by the U.S. Environmental Protection Agency (EPA). Lead could be ingested from hand-to-mouth contact after handling the lights or released into the air during installation and removal. Since lead is especially dangerous for children, we recommend that children are not permitted to touch the lights. As a basic safely rule, anyone who handles Christmas lights should wash their hands immediately afterwards.

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