Case Studies

CASE 1: Spray Painting Hazards at a Window Fabrication Facility

Background

OHCOW was asked  by worker and management representatives to conduct a hazard assessment at a manufacturing facility. The concern was potential exposure to contaminants encountered by workers when spray painting windows. The issues were:

• the type of PPE available to workers: respiratory, hand and skin protection
• ventilation in the spray painting area
• the composition of cleaning and painting products
• work practices such as the number of workers allowed in the spray booth
• elevated exposure risks during maintenance tasks such as changing the spray booth exhaust filters.

Intervention

An OHCOW Occupational Hygienist carried out extensive information gathering with location personnel through phone calls and email exchanges. This information included interviews, photos, videos, and  product Safety Data Sheets. A walk-through occupational survey of the facility and the spray painting area was conducted by the hygienist and worker-certified JHSC representatives, a regional EHS manager, two spray painters, and the spray-painting area supervisor. Observations and discussions during the tour formed the basis of recommendations for the paint-spray activities including ventilation and PPE considerations.

The workers' respirators, gloves and whole-body suits were evaluated for appropriateness of selection, use, care, and maintenance.  Smoke tubes were used for qualitative measurement of airflow/ventilation effectiveness in the cleaning (with acetone prior to paint application), paint mixing and spraying area.  Information on maintenance procedures (e.g. spray booth air filter change-out) through discussions with workers, supervisors and the regional health and safety manager.

Well-known safety resources were used in the hazard assessment for the booths, including the text  ACGIH Industrial Ventilation – Manual of Recommended Practice for Design.

OHCOW Impact

OHCOW’s observations and applicable technical references demonstrated that, to minimize exposure, only one worker at a time should be in the walk-in spray booth. Enhanced PPE protection consisting of more efficient respirators, gloves and whole body suits was also advised. These recommendations were agreeable to all parties.

After consultation with product suppliers, OHCOW provided updated information on the potential hazards of the substances used. The Safety Data Sheets at the facility were out of date and some were incomplete. OHCOW applied up-to-date scientific research to determine the nanomaterial content and carcignogenic classification of the materials.  Their findings were consistent with the use of the precautionary principle and the implementation of a high level of engineering (ventilation), administrative (proper use of the walk-in spray booth – only one user at a time) and PPE (HEPA/organic vapor respirators and full skin protection).

Recommendations were made to minimize exposure when workers changed the spray booth air filters, including better ventilation and PPE.  Detailed recommendations for air monitoring methods were provided based on the assessment.

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Case 2: McIntyre Powder-Exposed Workers with Lung Cancer

Background

McIntyre powder (MP) was a “prophylactic” treatment intended to prevent silicosis in gold and uranium miners. The substance was a fine aluminum dust that was developed at McIntyre Mine in Ontario. This “treatment” spread around the world. Ontario gold and uranium mines starting using MP in 1943.

The MP program ended in 1979, several years after it was realized that MP did not in fact reduce silicosis as it intended. The miners who inhaled MP have reported to OHCOW that they disliked this program. Research, including that conducted by staff at OHCOW, has found that MP caused adverse health effects such as Parkinson’s disease and lung disease. Other health effects are still under investigation. The miners also had other occupational exposures, including arsenic, asbestos, diesel exhaust (DE), radon, and respirable crystalline silica. All of these agents are lung carcinogens.

Intervention/Approach

A cohort of deceased miners with denied compensation claims for lung cancer was reviewed by a dedicated team of occupational hygienists. The team lead started by preparing a single generic report outlining the common exposures in gold and uranium mines, including the levels of risk posed by the exposure levels expected. The team moved onto individual reports, summarizing the individual’s occupational exposures and appended the generic report.

The family of “the Worker” submitted a claim for lung cancer for their beloved family member, who died of lung cancer. The Worker was employed nearly 30 years in underground gold and uranium mining. He worked mostly as a driller, rock bolter and machine operator, though he also held other jobs for short time periods. In his jobs, he would have been exposed to respirable crystalline silica (RSC), diesel exhaust (DE), radon, arsenic, asbestos, as well as MP. His exposures were estimated using the Ontario Mining Exposures Database (OMED) as well as data collected at Ontario mines in the 1970s and published in the peer-reviewed literature by Verma et al. (2014), and diesel exposure data published in a review by Pronk et al. (2009).

The Worker’s estimated exposures were compared to the health-based exposure limits, including occupational exposure limits (OELs) defined by the ACGIH as Threshold Limit Values (TLVs) and evidence-based levels evaluated by occupational hygienists at OHCOW. It is probable that the Worker was routinely exposed to RCS levels exceeding the ACGIH TLV, and diesel exhaust levels exceeding the recommended levels by OHCOW. In addition, his total radon progeny exposure exceeded the current Ontario OEL for radon progeny, made under the Mines and Mining Plants regulation. The Worker’s probable arsenic and asbestos exposures were likely below the current OELs; however, these exposures may have contributed to his overall risk since research suggests that carcinogens acting on the same target organ should be presumed to be at least additive. Finally, the Worker was also exposed to MP, which is not a lung carcinogen, but research has shown may contribute to the lung overload effect.

As a result of the team’s work, the occupational claim for lung cancer was accepted.

OHCOW Impact

Reviewing workers’ compensation claims makes a huge measure of difference to injured workers and the families of deceased workers. Workers’ compensation will ensure the proper healthcare is made available to workers undergoing treatment, and can provide financial support relating to their treatment. For deceased workers where the occupational disease contributed to cause of death, widows/widowers and dependent children may also be eligible for death-related benefits, including survivor benefits and reimbursement for funeral services.

Of course, OHCOW’s primary goal is the prevention of occupational diseases and injuries, but we also support workers who have been occupational exposed to hazardous agents in the past, too. This is done several ways: OHCOW nurses provide counselling on activities to further reduce risks, OHCOW physicians provide recommendations for screening activities, and, as with the Worker’s file, OHCOW occupational hygienists investigate retrospective exposures to estimate risk based on risk levels identified in peer-reviewed scientific literature. This focus on past work exposures and resulting occupational diseases is crucial to inform preventative measures for current workers, such as the recent reduction in the Ontario occupational exposure limit for diesel exhaust particulate in underground mining.

OHCOW recognizes that a claim for a deceased worker cannot provide adequate comfort the the family for their loss. However, OHCOW hopes that a small measure of comfort and additional financial security can be available to the surviving next-of-kin.

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CASE 3: Cancer Cluster Among Workers at Vocational College

Background

The Client was approached by a group who had worked in the same building of a vocational college and had been diagnosed with cancer.  The building trained students for industrial work, such as welding. The Client, the JHSC and the Union had noted health and safety concerns over several years but these were dismissed by management. The types of cancers varied, and the workers had different work and exposure histories at the college.  

Intervention

OHCOW coached the committee on how to work with Clinical and Prevention related services. On the Clinical side, OHCOW required interviews in a confidential setting with workers to collect information and determine the role of the work environment in their illness. The workers were advised to participate in the investigation and share their work history with the medical staff. It was necessary to understand the workplace dynamics and the internal responsibility system as part of OHCOW's information gathering. 

On the Prevention side, OHCOW provided a multidisciplinary team to advise the JHSC and Union Membership on how to respond to the health and safety issues being raised. Conducting an Indoor Air Quality Assessment (IAQ) was the top priority. The hygienists gathered information such as the parameters to be measured, the locations to be sampled, and anecdotal information provided by the Committee. Written logs of work practices in the various classrooms also assisted the investigation. Based on previous IAQ assessments, OHCOW was able to provide recommendations and interpretation of the data presented to help the client understand the exposures and why there were higher levels of contaminants in one areas versus another.   

Impact

OHCOW recommended installing local exhaust ventilation in one of the welding classrooms. In the interim when ventilation was not sufficient, PPE for workers should be provided. Support for the Client continues, such as preparation for meetings with Management, and advising on recommendations that the JHSC and the Committee puts forth in writing. 

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Case 4: Toxic Exposure during Pharmaceutical Manufacturing 

Background

A small veterinary medicine manufacturing company contacted OHCOW requesting an assessment of exposure during the manufacturing of the medical substance phenylbutazone. A nonsteroidal anti-inflammatory medication, Phenylbutazone was discontinued for humans due to its severe adverse health effects such as blood dyscrasias, anemia, bone marrow suppression and other risks. However, it is still used for animals, particularly racehorses. Workers at the manufacturing plant were concerned about potential adverse health effects during the manufacturing process, and were experiencing respiratory irritation. They requested an assessment of the current controls in place, such as the ventilation and respirator use, to determine if these are adequate enough to minimize or avoid the exposure.

Intervention

An occupational hygiene assessment was carried out. OHCOW hygienists discussed the issue with the JHSC members and conducted a walk-through survey of the facility to understand the manufacturing process and the ventilation system. The dust exposure during weighing and mixing was measured with specialized equipment. Two dust measurement instruments — Dusttrak and P-track — were used. To interpret the results, a health-based exposure limit had to be derived. Since there was no occupational exposure limit for phenylbutazone, control and exposure banding tools had to be used to derive a limit. OHCOW hygienists conducted further research into the highly toxic substance to determine a sufficient exposure limit.

After research and testing, OHCOW found that the majority of the dust readings were higher than the exposure limit. While the general ventilation appeared to have high air changes per hour, the dust generation rate overcame the high ventilation rate, therefore, it was not adequate to reduce the direct exposure. It was also determined that the respirators in use did not have a high enough protection factor. Musculoskeletal hazards were identified during the manual loading and unloading of the active and nonactive pharmaceutical ingredients into the mixing blender.

OHCOW Impact

To lower the exposures, recommendations were provided following the principle of Hierarchy of Control.

1. Engineering controls were recommended, such as enclosing the mixing area, maintaining a negative pressure to keep the dust inside the room and installing a local exhaust ventilation at the discharge and loading site of the mixer.
2. It was advised that workers receive better education and training, such as information about the product’s health hazards, as well as proper use of respirators and the local exhaust ventilation system.
3. It was recommended that the pace of the work should be reduced to a level at which workers can follow ergonomic principals of lifting and avoid MSDs.
4. In general, the use of personal protective equipment is the least preferred method of protection, however, in this case it can play an important role owing to the toxicity profile of the medicine. A respirator with an adequate protection factor was recommended and different web-based tools were also provided for workers to consult.

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Case 5: Nickel Processing Plant Operator Multiple Exposed to Carcinogens

Background

Many workers in both nickel processing and underground mining have exposures to multiple carcinogens. This Worker, who unfortunately is now deceased, initially had his claim denied. This was overturned after collaboration between an occupational hygienist and occupational physician at OHCOW resulted in a successful claim. The Worker had been diagnosed with Stage III, Squamous Cell Carcinoma of the lung. He, along with many workers, were simultaneously exposed to group 1 (IARC 2018), lung carcinogens, including nickel and nickel compounds (IARC Monograph 100C), diesel exhaust (IARC Monograph 105), asbestos (IARC Monograph 100C) and respirable crystalline silica (RCS) (IARC Monograph 100C).

Intervention/Approach

The retrospective exposure review (RER) reports, when comprehensively written, incorporate the latest epidemiology and can be considered as “sentinel reports.” The findings provided evidence that occupational exposures contribute substantially to the burden of disease otherwise considered idiopathic and labeled “IPF”, and squamous cell lung cancer. The reports also provide updates to the WSIB which challenges outdated policies and policy manuals. Apart from providing estimates of exposure, to the four previously discussed group 1 carcinogens, the report also emphasized the importance for the WSIB to take into account “combined occupational exposures” to established lung carcinogens which is in line with leading occupational hygiene practices. It was further noted that when a smoker has occupational exposures associated with lung cancer, the combined effect of smoking plus occupational exposures has interaction effects that are greater than additive, up to multiplicative.

OHCOW Impact

As the sentinel retrospective exposure reviews are provided, this paves the way for the latest epidemiology to be incorporated. This is especially important where claims are successful as they keep the worker advisors and adjudicators abreast of the latest information. It also provides a pro forma for subsequent case reports where workers have been in similar exposure groups with the same disease outcomes. Once again, this report reinforces the combined effects of exposures and reiterates the combined effect of smoking plus occupational exposures. Many workers in Sudbury will have been exposed to elevated exposures to nickel along with the other carcinogens previously noted. Exposure to various nickel compounds increases the risks of both lung cancer and nasal cancer.

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Case 6: Milton Courthouse Shutdown Due to Mould

Background

The Milton courthouse was shut down by a criminal court justice following reports that the building, which had a history of water leakage, had substantial mould. Courtroom staff had stopped working in their offices due to the potential adverse health effects. The employer hired a private consultant to perform mould testing whose sampling, done through the total spore count method, did not detect any significant level of mould in the air. Courthouse staff requested a third-party analysis through their union (OPSEU). The OPSEU staff representative contacted OHCOW to review the mould reports and also  determine if workers' health had been impacted by the  presence of mould.

Intervention

The OHCOW Occupational Hygienist reviewed the reports and provided an analysis to the union representative both verbally and in writing. The report determined that the sampling technique used by the consultant hired by the employer — i.e. the total spore count —  is only useful to compare the mould spore levels in different areas in order to find the source, and not to correlate mould with workers' symptoms. The technique is prone to misleading interpretation of the results because the measurements can vary due to factors such as different ventilation rates within a building, the location of sample in relation to the mould growth, and more. Due to these challenges, it is usually recommended by different guidelines (NIOSH, Health Canada IAQ guideline) that a mould investigation should start with visual inspection, detection of musty/mould odour, investigating dampness in the air and building material, noting any history of water leakage, and taking bulk samples if mould is suspected.  The guidelines discourage air sampling when mould is identified in a bulk sample, and recommends remediation of the mould growth without doing further air sampling. The scientific literature shows that occupants of buildings with damp conditions and history of water leaks are likely to show respiratory adverse health effects.

Since workers at the courthouse were concerned about mould exposure and its impact on their health, a qualitative tool developed by NIOSH would be helpful. The tool has shown correlation between damp conditions in a building and occupant health effects. The recommended tool was provided to the union staff representative to carry out a qualitative assessment and determine if workers had mould exposure-related symptoms.

OHCOW Impact

The employer fixed the water leaks on an urgent basis and remediated all the ceiling tiles with mould. The staff returned to work after the remedial work was completed.

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Case 7: Administering Methoxyflurane Analgesic Exposure Poses Health Risk

Background

A hospital sciences centre in Ontario requested that OHCOW provide an independent assessment to determine the risks for health care workers who administer Methoxyflurane (Penthrox®), and to make recommendations for safe handling. This analgesic is a hand-held inhaler for short term relief of moderate to severe pain associated with trauma or medical procedures in conscious adults. Methoxyflurane has been used for anaesthesia, however evidence of nephrotoxicity (causing kidney damage) led to abandonment of this application. Subsequently, methoxyflurane in lower doses has re-emerged as an “analgesic agent.” Even though this analgesic has been approved for use by Health Canada, unless it is administered following proper safety protocols, there may be a risk for Ontario health care workers who handle it.

Intervention/Approach

The OHCOW Occupational Hygienist and Occupational Physician delivered a report to the hospitals in question outlining the risks for health care workers, based on the most up-to-date medical literature. The report concluded that the workers administering methoxyflurane to patients are at risk of inhaling local environmental methoxyflurane. The substance can be metabolised to fluoride and can interact with health factors specific to the individual worker. Health consequences of the exposure and metabolism could potentially include renal injury, hepatic injury, skeletal fluorosis and reproductive risks. This poses legal risk to the employer. To understand the level of exposure to methoxyflurane, along with metabolite produced (fluoride), it has been recommended that personal exposure monitoring and biological monitoring be carried out. A review of current (control) practices has also been recommended.

OHCOW Impact

This inquiry / group work opens the door to work more collaboratively with hospitals throughout Ontario. It allows for a more independent review of health risks from exposures to both waste anesthetic and analgesic drugs, which can also be shared throughout hospital networks and with joint health and safety committees (JHSCs).  Furthermore, it paves a way for OHCOW to provide hazard alerts. One hospital occupational hygienist reported back that this work “acts as a prompt.”

Even though use of this analgesic is restricted to areas of the hospital with appropriate facilities / equipment and trained staff, they have not historically included it as part of their anesthetic gas monitoring program. They are now considering including its use in the program, based on further review which will be ongoing. OHCOW will continue to provide awareness about the hazard and risks from administration, along with safe use, to help with risk benefit analysis conducted by hospital in collaboration with JHSCs.

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Case 8: Idiopathic Pulmonary Fibrosis in Foundry Worker 

Background

At the time of referral, The Worker was 65 years old and had been referred by his advocate to The Occupational Health Clinics for Ontario Workers (OHCOW). The Worker had been employed in construction and foundry work for over 40 years in various capacities. He also worked previously as a truck driver and a painter. 

He was diagnosed with Idiopathic Pulmonary Fibrosis (IPF) and submitted a claim to the Workplace Safety and Insurance Board (WSIB). His claim was denied.  The eligibility adjudicator based the refusal on a hygiene assessment and a medical consultants' report that concluded it was not possible to establish that the Worker's illness was caused by the occupational environment. A significant weight was placed on the fact that the worker hasd a significant smoking history of 36 packs per year.  

Both non-occupational and occupational risk factors have been identified as contributing for diagnoses of IPF.  Intrinsic factors may include male gender and age, family history of the condition, gene mutations, and more. Cigarette smoking is an extrinsic risk factor for the disease.  In this particular case, the issue was not whether or not the diagnosis had been confirmed, but rather what caused the Worker's diagnosis.   

Intervention/Approach   

 The file was referred to an OHCOW Occupational Hygienist to complete a retrospective exposure profile of the Worker’s Occupational exposures. The hygienist concluded through an interview that the Worker faced an increased risk of developing pulmonary fibrosis and lung cancer due to cumulative exposures in the workplace to multiple contaminants. Exposure to substances such as respirable crystalline silica, diesel exhaust and asbestos, independently raised his risk to nearly twice the normal level. The hygienist's report cited studies that showed the increased risk persisted even after accounting for the impact of smoking.  

The file was then referred to an OHCOW Occupational Medical consultant for review, who found that the worker had an extensive history of Occupational exposures to agents statistically linked to IPF in epidemiologic studies. These exposures included metal dusts (nickel, iron, copper), silica dust, asbestos dust, and a nonspecific category referred to as VGDF (respirable dust, diesel exhaust, sulphuric acid, sulphur dioxide).   The total duration of exposure over 40 years aligns with findings indicating a significant increase in risk  for those with 20 years or more in at-risk jobs.  

The diagnosis of IPF by the Worker’s treating physician was deemed appropriate by the OHCOW medical consultant. The consultant was able to provide a supportive medical reporting concluding: “The available evidence does not support a conclusion that worker’s lung disease is idiopathic, i.e., has no known cause.  On the contrary, the available evidence indicates that his lung disease, Idiopathic Pulmonary Fibrosis, was caused by the occupational exposures described.  Smoking cannot be ruled out as an additional contributing factor.”  

OHCOW Impact

OHCOW's reports were submitted to The Workplace Safety and Insurance Board (WSIB) by the estate’s advocate to reconsider the entitlement in this claim. The decision to deny entitlement was overturned. As a result, the estate returned a positive feedback form to OHCOW and thanked staff for all their efforts. 

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Case 9: Esophageal Cancer in relation to Asbestos Exposure

Background

The worker was diagnosed with esophageal cancer. His initial claim for entitlement benefits, attributing his occupational exposure to his onset of disease, was denied. The evidence was found to be inadequate to conclude the presence or absence of a causal relationship between asbestos exposure and esophageal cancer. WSIB Policy identifies the esophagus as part of the gastrointestinal tract, however, internal WSIB advice documents exclude it from consideration under the policy. As such, the claim was not adjudicated under WSIB Policy, but instead on a case-by-case basis. The worker’s 30-year employment history with General Electric’s Peterborough facility, from 1974 to 2009, involved work primarily as a fitter-assembler & tack welder. His jobs duties involved various types of welding operations such as electric arc welding and machining components such as gaskets for commutator assemblies.   

Intervention

OHCOW hygienists sought to support this claim by: 1) characterizing his asbestos exposure; 2) providing relevant epidemiological evidence of association between asbestos and esophageal cancer and; 3) supporting our information with a related Workplace Safety and Insurance Appeals Tribunal (WSIAT) decision.  

The hygienists curated useful information from the claim file, such as the worker’s employment history and historic workplace inspection reports. All available historic reports were inventoried in a dynamic database, which searchable by asbestos exposure data, building location, job title, and era of work. Next, a review of relevant epidemiological literature and WSIAT decisions was performed. Finally, an occupational hygiene (OH) report template was created to provide concise OH information and opinion for the consideration for possible WSIB appeal submission. A brief summary of the review of the scientific literature and the WSIAT decisions have been outlined below:  

Based on the WSIB’s interpretation which excluded the esophagus from consideration under Policy 16-02-11:  

The current OHCOW assessment included a search of the scientific literature for recent published articles relating to esophageal cancer and work. A 2021 Taiwan systematic review by Wu et al. was identified. This paper showed a positive association between asbestos and esophageal cancer. This recent epidemiological evidence suggested that the worker’s claim of esophageal cancer should be reconsidered under Policy 16-02-11 with respect to his potential occupational exposure to asbestos. 

OHCOW hygienists examined prior WSIAT decisions that involved the application of Policy 16-02-11. The review identified a WSIAT decision involving esophageal cancer where the Tribunal accepted the diagnosis of esophageal cancer as one of the gastro-intestinal cancers covered by Policy 16-02-11. WSIAT also provided a broad definition of an asbestos worker as having direct or indirect exposure resulting from the use of asbestos equipment, asbestos tools, and asbestos materials. OHCOW hygienists noted that WSIAT established an era (prior to the early 1980s) and minimum years of exposure (6 years). OHCOW hygienists were able to show clear and adequate history of exposure, and that the nature and pattern of such work was considered continuous and repetitive, and consumed most of the worker’s job duties.  

OHCOW Impact

This case strengthens the work-relatedness of esophageal cancer and exposure to asbestos specifically prior to the mid-1980s. Through the work on this case OHCOW hygienists were able to create an Occupational Hygiene report template using standardized text and a thorough examination of all available information. This approach will allow for timely, concise, and consistent exposure assessments of similar types of denied claims, i.e. the exclusion of esophageal cancer from consideration under Policy 16-02-11. 

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Case 10: Pipefitters' Lead Exposure

Background

OHCOW received an inquiry from a Toronto Occupational Health Nurse by way of a union Health and Safety representative. The inquiry concerned measurable health-risk legacy from residual dust exposure and contamination from pipefittings. The old pipes used a lead-based sealant that is no longer in use, and there was a risk of potential adverse health effects from lead exposure. The lead dust gets on workers' hands and clothes, as well as contaminating surfaces. 

Intervention/Approach

An OHCOW team was established to work with the union to address the lead contamination issue. Other pipefitter groups across the province have been identified as likely having used or may still be using the same leaded pipe sealant. 

Lead exposure has occurred in the trade through the pipe sealant, or pipe dope, known as “Masters Metallic.” It is still “readily available” for consumers and contains about 80% lead in a paste form. In some workplaces  this lead sealant has been replaced by a lead-free sealant, yet there remains a serious exposure from ingestion of the lead contaminated dust that is still present. "Take-home" lead dust that remains on clothing, skin and hair, can effect the home environment, increasing the “blood lead” of children and other family members. Measurable lead dust has been identified in old fittings which has been shown in trucks, and many other fixtures. This thread sealant remains currently available on store shelves for contractors and homeowners to use which is alarming. 

Results

The following initiatives are underway to address the issue:

• OHCOW will be consulting with researchers in both the US and Canada on the use of X-ray Fluorescence Scanning (XRF), the best method to assess the long-term body burden of lead. Currently the service is not available in Canada.
• Various efforts in information transfer relating to the health risks of lead exposure are being developed.
• A booklet on the topic is being developed and will be distributed through union representatives and other contacts. Older materials about lead in the OHCOW online archives,will be updated.
• Seminars, both in person and virtual, have been presented to the relevant audiences and is continuing. A presentation was made at an inter-union conference with Canadian and American Pipefitters. OHCOW staff also presented the lead exposure issue to Occupational Health Physicians at the virtual American College of Occupational and Environmental Medicine (ACOEM). A presentation for the American Occupational Health Nurses virtual conference June 2024 is planned. 

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