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93 Skyway Avenue, Suite 101
Toronto, Ontario M9W 6N6
Since 1979, we provide unparalleled environmental services to our clients.
Our teams include Certified Industrial Hygenists & Registered Occupational Hygenists.
Our training programmes include legislation & working with hazardous materials.
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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.
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.
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.
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:
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
Authors: Christopher Nielsen & Angeline Snow
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.
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.
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.
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.
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.
93 Skyway Avenue, Suite 101
Toronto, Ontario M9W 6N6