A respirator is just a mask for a problem!

Safety Solutions at Work would like to address a serious problem that we are witnessing in industries across the province.

Employers are asking their workers to wear respirators as personal protective equipment.  However, the respirators are being assigned without fully understanding the hazards involved.  This newsletter explores the importance of occupational hygiene testing in order to properly manage the risk of workers being over-exposed to dangerous substances.

Here is some background into how companies should control exposure to dangerous substances: The Hierarchy of Hazard Control.

Hierarchy of Hazard Control

The diagram below shows the control hierarchy, with the more preferred measure on top.


  1.  Elimination of Hazard, which is the process of removing the hazard from the workplace. It is the most effective way to control a risk because the hazard is no longer present.

  2. Substitution, which refers to substituting the hazardous chemical/industrial process with a less hazardous one. Replacing currently used chemicals with  less toxic ones is an important part of  industrial evolution.  

    Here is an interesting example: Diacetyl was previously widely used to provide the buttery flavouring to popcorn. Twenty years ago, epidemiology studies and case reports revealed its effect of reducing lung function among popcorn making workers. Nowadays, 2,3-pentanedione is used as a safer substitute for diacetyl to produce butter-flavoured popcorn. However, substitution is not on the top of the hierarchy, because no chemical is absolutely safe. In the example of popcorn flavouring, more recent studies revealed that 2,3-pentanedione will reduce lung function as well.  Ongoing monitoring of all chemicals is essential.

  3. Engineering controls are the methods that are built into the design of a plant, equipment or process to minimize the hazard. Examples would be process control, LEV (local exhaust ventilation) and hazard isolation.

  4. Administrative controls  limit workers’ exposures by scheduling shorter work times in contaminant areas or by implementing rules and company policies to reduce either the time or the number of workers being exposed. The efficacy of administrative controls is subject to a variety of human factors.

  5. PPE is on the bottom of the control hierarchy, which means it is the least preferred method. Personal protective equipment (such as respirators) should never be the only method used to reduce exposure. The reasons this are further explained below.

Limitations of PPE

  • PPE may fail with little or no warning. For example: “breakthrough” can occur with gloves, clothing, and respirator cartridges, and the consequence of relying on it as the sole way of control could be catastrophic. Air-purifying respirators cannot be used for gases and vapours with poor warning properties, especially when end-of-service-life indicator is not available. Air-supplying respirators, on the other hand, although supply clean air from air tank or compressor, have limited mobility and require a larger purchasing/maintenance budget.

  • The absorbing material inside cartridges and filters of air-purifying respirators may not be efficient for certain contaminants. Examples of such contaminants are nitrogen dioxide, nitric oxide and nitrous oxide.

  • There is an assigned protection factor (APF) for each specific respirator.  Air-purifying respirators for example,  have an APF of 10 to 50. An APF of 10 to 50 means that if the respirators were fit tested, being worn properly by the worker and not being broken through, the theoretical exposure level that the worker is expected would be 1/50 to 1/10 of  a worker who is unprotected. However, the actual protection efficiency may not be achievable, due to the various human factors. For example, the APF will be reduced if workers are not clean shaven.  Getting men to shave every morning is no easy task!

Necessity of Exposure Assessment

WorkSafeBC OHS Regulation mandates the following workplace monitoring procedures:

  • When a worker is or may be exposed to a hazardous substance, the employer should ensure that a walkthrough survey is conducted to assess the potential for overexposure taking into account all routes of exposure.

  • If the walkthrough survey reveals that a worker may be at risk of overexposure to an airborne contaminant, the employer must ensure that air sampling is conducted to assess the potential for overexposure. 

  • Additional workplace monitoring to reliably determine worker exposure is required if a worker may be exposed to an air contaminant in excess of 50% of its exposure limit.

Currently, WorkSafeBC regulates the maximum allowable exposure level for around 800 substances. It is the employer’s responsibility to ensure that the workers are not exposed to levels higher than indicated by WorkSafeBC Exposure Limit. Only by doing a hygiene testing can you make definitive conclusions. A complete list of these substances and exposure limits can be found in G5.57 of WorkSafeBC OHS Guidelines.

In addition to meeting the WorkSafeBC regulation requirements, conducting air quality testing can also provide you with the following key information:

  • The assigned protection factor (APF) for a disposable facial mask is 5 for single use facial mask, and is 50 for air-purifying half mask. If the workplace is heavily contaminated (i.e. above 5 times of Occupational Exposure Limit), the use of respirators, even under ideal conditions, will fail to provide workers with sufficient protection.

  • Air quality testing should be conducted before and after  installing  engineering controls, to evaluate its efficiency.

  • Each year WorkSafeBC receives claims of occupational disease claims. Conducting  industrial hygiene testing and documenting the report could demonstrate the employer’s due diligence in recognizing and evaluating workplace hazards.

Posted on: February 26th, 2023 by Phil Comments

Occupational Health among Mill Workers: Risk, Exposure and Prevention

Did you know that mill workers are exposed to life threatening hazards which are invisible killers?

Did you know that most of the catastrophic accidents that we have seen in mills are actually preventable?

These are the questions I came up with while reading WorkSafeBC’s incident investigation report regarding the Burn Lake’s Babine sawmill explosion, which killed 2 workers and injured another 20. Wood dust (accumulated into high levels and dispersed into a “cloud” suspended in the air), ignition sources, and oxygen in the air constituted the necessary components of the fire triangle, which directly lead to the catastrophe.

If we take a step back and think of any workplace, how confident are we in saying that “our company is a pretty safe place to work”?

Have we eliminated all of the potential hazards such as fire triangles, explosions and chemical exposure?

Sawmill Workers’ Exposures to Occupational Hazards

  • Wood dust:  Short-term exposure to wood dust could be irritating to the skin, respiratory tract and eyes. Wood dust is also proven to be associated with decreased lung function and asthma.
  • Spores, fungi, microbes and endotoxin: These microorganisms and bio-chemicals are irritants to the nose, throat and eyes. They might lead to COPD (Chronic Obstructive Pulmonary Disease) and aggravation of pre-existing conditions such as asthma.
  • Wood preservatives: Certain chemicals used for wood preserving are classified as carcinogens by IARC (International Agency for Research on Cancer) and ACGIH (American Conference of Governmental Industrial Hygienist), which means that they have the potential to cause cancer. Examples of such chemicals are pentachlorophenol (a.k.a. PCP), creosotes. Some of the chemicals are corrosive to skin, eyes and respiratory tract, such as phenol.
  • Heavy metals: Sawmill workers in the maintenance department can be exposed to heavy metal from their welding, grinding and knife-sharpening activities. Some sorts of heavy metal can decrease lung function, while others may cause cancer.
  • Evaporated chemicals in pulp cooking: Examples of such chemicals are ammonia, hydrogen sulphide, sulphur dioxide and methyl mercaptan. Health concerns over such chemicals are short-term acute toxicity (i.e. IDLH, Immediately Dangerous to Life or Health).

An Example of Elevated Risk

Safety Solutions at Work’s occupational hygienist,  Phillip Chen, completed a detailed epidemiology study which associated COPD (Chronic Obstructive Pulmonary Disease) with endotoxin exposure among sawmill workers. Endotoxin is produced by bacteria grown on wood.  

In the wood processing industry, endotoxin is released along with wood dust when certain tasks are performed, such as cutting, sawing and trimming, and then can be inhaled by sawmill workers. After adjusting for confounder such as age, race, smoking and lagging time (20 years), based on the Poisson regression model, the risk of COPD among highest exposed group doubled that of the reference group (Relative Risk 2.09, 95% CI 0.9 – 4.83).

Currently ACGIH, U.S. OSHA and WorkSafeBC is not regulating endotoxin. Phil is hoping that the disease model he built can serve as a piece of evidence in setting up exposure limits for endotoxin to protect the respiratory health of sawmill workers.

Seeking a Solution from Safety Solutions at Work’s

Based on WorkSafeBC’s incident investigation report, the tragic accident of the Babine sawmill in Burns Lake was preventable by eliminating any element of the fire triangle. If the wood dust is not accumulated into high concentration, or if the wood dust is not dispersed in a way to be explosive, then we won’t have to pay the lesson at the cost of two workers’ lives. Similarly, for the chemical and biological exposures which could lead to occupational diseases, as an employer, you can demonstrate your due diligence by starting an occupational hygiene survey to evaluate the potential hazard level. Here is  Safety Solutions at Work can help you:

  • As an OHS consulting company, Safety Solution at Work aims at promoting overall health and safety in different industries. We believe that risk assessment should be the foundation of risk management.
  • The MSc. thesis research project of our occupational hygienist Phillip Chen was focused on the respiratory health among sawmill workers in BC, as part of the UBC Sawmill Study. He is passionate about protecting workers from the negative heath effects of heavy metal and endotoxin exposure. He is dedicated to conducting occupational hygiene risk assessments in mills across this province.
  • If a company is not sure of the chemical hazards your workers encounter, we can work with you on a hazardous material inventory for your plant.  Air testing is the very first step in creating a safe and healthy work environment, and we can work with you to achieve it!
  • We can also assess other risks in the mills, such as noise, vibration and explosive dust.

You are the voice of safety in your workplace.  If you have concerns about hazards, it is your responsibility to speak up.  Let your supervisors, safety committee members, management representatives and shop stewards know about your concerns.  Speaking up is the first step to take action.

Posted on: January 23rd, 2023 by Phil Comments

Vibration: Not always fun!

For the past few weeks, I have spoken with a few clients regarding the concern over occupational exposure to vibration. So for October’s newsletter, I will be focused on the generation, evaluation and control of occupational exposure to hand-arm vibration.

Vibration: Not always fun!

We may come across vibration through our daily life, such as the one that Mrs Brown is exposed to in the following video:

However, as an OHS consultant, we focus only on vibration which is generated at workplace and which may harm you. This type of vibration includes Whole Body Vibration (WBV) and Hand-Arm Vibration (HAV). WBV enters the whole body through a vibrating floor or seat, which could happen among vehicle/heavy equipment/marine operators. HAV, which attracts most of the concern over vibration, affects the hands and arms. Hard-arm vibration is ubiquitous across the industry, which could happen among operators of chain saws, chipping tools, jackhammers, grinders and others who operate hand-held vibrating tools.

Why should vibration be of concern?

Hand-arm vibration is associated with a variety of health outcomes:

  • Neurological effects. The health outcomes are progressive, which include: numbness, tingling, reduced sensory perception and dexterity.
  • White finger (WF) syndrome, which refers to the attacks of whitening (i.e. blanching) of one or more fingers when exposed to cold. Vibration-induced white finger is the most common syndrome among workers using hand held tools.  The development of WF syndrome is gradual, which may take several years to develop. If you take measures after the worker’s fingers have blanched, IT IS ALREADY TOO LATE!
  •  White finger syndrome
  • Raynaud’s phenomenon, which refers to a disorder of blood circulation in the fingers and toes. This condition aggravates with cold exposure. Crucial facts: 50 percent of 146 tree fellers examined in British Columbia had Raynaud’s phenomenon. 30% of 1540 forestry workers in Quebec had Raynaud’s phenomenon. After 20 years of chainsaw use, over 50% the workers had Raynaud’s phenomenon. (Resourced from Canadian Council of Occupational Health and Safety)

What are the regulations out there for HAV?

Vibration exposure can be quantified by acceleration, which is a measure of how quickly speed of vibrating object changes with time. A complete assessment of exposure to vibration requires the measurement of vibration acceleration in meters per second squared (m/s2). Vibration exposure direction is also important and is measured in a well-defined directions.

American Conference of Governmental Industrial Hygienists (ACGIH) sets up exposure limit for hand-arm vibration, which is then adopted by jurisdictions such as WorkSafeBC. The standards are summarized in the table below. It is the employer’s responsibility to ensure that the workers are not over-exposed to the limits stated below.

Total daily exposure duration TLV of the dominant axis, frequency-weighted, rms, component acceleration
4 hours and less than 8 hours 4 m/s2
2 hours and less than 4 hours 6 m/s2
1 hour and less than 2 hours 8 m/s2
less than 1 hour 12 m/s2

 What should I do if vibration is of concern at my workplace?

  • Initiate the measurement right away. Several variables may determine the worker’s exposure to vibration, such as duration, types of tools used, worker’s posture and hand-grip force. Only through personal measurement performed following industrial standards can you assess vibration exposure and make sure that the workers are not over-exposed. Safety Solutions at Work is pleased to announce that we provide occupational hygiene services, which includes vibration measurement!
  • Be aware of noise too! CCOHS suggests that there might be a correlation and combining effect between vibration and noise exposure: Since most vibrating machines and tools produce noise, a vibration-exposed worker is likely to be exposed to noise at the same time. Studies of hearing loss among lumberjacks revealed that, for equal noise exposure, those with vibration-induced white finger (VWF) had greater hearing loss than those without VWF. The reason for this effect is still unclear. Safety Solutions at Work can perform the measurement of noise and vibration at the same time, thus significantly reduces the cost of survey.
  • Choose your tools wisely. If possible, choose vibration reducing hand-arm tools.
  • PPE. There are vibration reducing gloves commercially available. However, it should be only used as supplemental measures, as their efficacy in reducing vibration with frequencies of highest risk of exposure is questioned.
  • Keep warm. Low temperature might also contribute to the blocking of circulatory system around hand and arm and might make the VFW syndrome more severe.
Posted on: October 21st, 2022 by Phil Comments

Protect the Hidden Victims of Workplace Hazards

This September is the 12th anniversary for the 911 attack. It is truly a tragedy for us to remember and commemorate; however, from an occupational health perspective, the tragic story is still going on, as the list of hidden victims keeps expanding.

With the collapse of the World Trade Center, building material such as asbestos and fiber glass were pulverized and spread all over the area. Firefighters, policemen, communication workers, and janitorial workers involved with the clean-up process are exposed to contaminants which are potential carcinogens or may cause permanent lung dysfunction.

However, it was not a long time ago since these occupational hazards were realized by the media and public health authorities, and the recognition and compensation remains to be an issue, which is demonstrated in the video below.

The Hidden Victim of 9/11 (Youtube)

This case reflects the dilemma faced by OHS professionals: On the one hand, the issue of workplace safety has been realized widely, and continuous effort has been put to eliminate them.

On the other hand, occupational diseases, as a result of the chemical, physical and biological exposure at workplaces remains to be unsolved: It is estimated by International Labour Organization (ILO) that almost 80% of fatalities at workplaces are caused by occupational disease. In Canada, many provinces have made great progress in reducing the number of workplace injuries. However, the overall number of work-related deaths remains unchanged. The reason is that deaths caused by work-related disease have increased steadily over the past two decades.

Why is occupational disease not getting the deserved attention in spite of the catastrophic outcomes?

First reason is that compared with occupational injuries, whose cause could be identified by accident investigation following certain procedures, the identification of occupational disease is much more complex. Of course we can indicate some chemicals as being “toxic”, but the definition of “toxic” is so broad that it hardly makes any sense in associating the certain disease with exposure. Take occupational cancer as an example, the International Agency for Research on Cancer (IARC) evaluated the carcinogenicity of around 900 chemicals; however, consider the numerous chemicals that exist at workplaces, those evaluated are just the iceberg above surface. 

The second reason for the lack of awareness is that occupational diseases seldom develop on a single day. Take occupational cancer for example: cancer is a chronic disease, the latent period between exposure and disease occurrence could be decades. This is a huge barrier when linking disease with exposure.

With so many gaps remaining to be filled, preventative approaches have been made to protect workers from the emerging risk of occupational risk: provincial regulations have set up exposure limits for the chemical, physical and biological hazards, and for those with potential to induce cancer and other permanent damage, it is the employer’s responsibility to keep the exposure level “As Low As Reasonably Achievable” (i.e. ALARA).

As part of the due diligence for employers, initiating an air testing is the fundamental step to prevent the occupational disease!

Posted on: September 16th, 2022 by Phil Comments

Introducing Occupational Hygiene Services!

Hello everyone, I am Phillip (Hanchen) Chen! I just joined Safety Solutions at Work as an Occupational Hygienist last month. It has been a fun month for me, especially when I walk into the workplace and introduce my role as an “Occupational Hygienist”.  I get amusing questions about my role as an occupational hygienist such as: “Are you responsible for keeping the patient’s teeth clean?” “Nope, but dental hygienists do”. “Do you remind workers to wash their hands?” “Yes, we promote workplace health, but we do more than that!”

So, what do Occupational Hygienists do beyond providing workers with soap?

Why do we need to use the soap? Probably because our hands are dirty. At workplaces, the “dirt” could be more complex with amorphous forms. A big part of our job is to recognize and assess the dirt!

Let’s suppose that when a worker walks into the factory to start his job, what could he be exposed to and what could harm his/her health? Chemicals for sure. Solvents, degreasers, resins could be released into the work environment and then the worker will inhale those into the lungs. Dust of course, especially when he works in a sawmill or welding shop. Noise and vibration are ubiquitous issues as well. So, as occupational hygienists, we can go to the field and assess worker’s exposure to this wide variety of chemical, physical and biological hazards.

Why do we do that? – To protect the worker’s health for sure!  The value of them being healthy at work is of key importance to the family, community and society. Also, provincial regulations  set up limits of these hazards!

Which kind of soap do choose? There are lots of factors to consider, such as your skin type, the cleaning efficiency and $$$. To fully protect workers from the occupational hazards, we also advise control measures, by taking all the factors into consideration. To achieve that, we work with civil and environmental engineers, safety engineers, chemical suppliers, protection equipment manufacturers and the employer to provide comprehensive protection to the workers.

“Hygiene” as a science, deals with the promotion and perseverance of health. In spite of the differences on the technical aspect, “Occupational Hygiene” deals with the health and well-being at workplaces, which is  consistent with the general concept of “Hygiene”. Thus, I would like to share a picture of Hygieia, who is the Greek goddess of health. It is nice to realize that the title on my card has sort of association with Hygieia.

Posted on: September 3rd, 2022 by Phil Comments

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