This resource does not replace the Occupational Health and Safety Act (OHSA) and its regulations, and it should not be used as or considered legal advice. Health and safety inspectors apply the law based on the facts they find in the workplace.

This guide was created for physicians to better understand the Code for medical surveillance for designated substances (the Code). It applies to employers that are required to provide for medical examinations under subsection 20(4) of 澳门永利 Regulation 490/09 — Designated Substances (O. Reg. 490/09 or the Regulation). For more information on this regulation, please consult A guide to designated substances in the workplace.

The Code is a minimum standard with minimum requirements that the examining physician must abide by.

Overview

For certain designated substances that workers may be exposed to in the workplace, employers must have a control program that provides for pre-placement, periodic, acute exposure and exit medical examinations, including clinical tests. These requirements are laid out in the Code for Medical Surveillance for Designated Substances.

Designated substances

Eleven chemical agents are prescribed as designated substances in 澳门永利, but only the following 7 substances require medical surveillance as part of the control program:

  • asbestos
  • benzene
  • coke oven emissions
  • isocyanates
  • lead
  • mercury
  • silica

If a worker has been exposed to one of the other designated substances (acrylonitrile, arsenic, ethylene oxide or vinyl chloride), the worker may undergo a medical examination and clinical tests if the worker, the worker’s physician or the employer has reason to believe that the worker’s health may be affected by the exposure.

Learn more about designated substances, which are defined in O. Reg. 490/09 — Designated Substances.

Learn more about asbestos in our guide to the regulation respecting asbestos on construction projects and in buildings and repair operations.

How workers are exposed to designated substances

Workers may be exposed to designated substances by inhalation, ingestion, skin absorption or skin contact. Learn more about the primary routes of exposure for each designated substance.

Responsibility for costs

The employer is required to bear the costs of:

  • medical examinations including clinical tests
  • the worker’s reasonable travel costs
  • the time the worker spends to undergo the examinations or tests including travel time

Employers must bear these costs regardless of whether or not the worker’s own physician performed the medical examination.

For more information, see subsection 26(3) of the OHSA and subsections 20(5) and 28(2) of O. Reg. 490/09.

Voluntary participation

Medical surveillance is only one component of a control program for certain designated substances. Where it is required, the prescribed medical examinations and clinical tests, as required by the Code, must be provided as part of a control program (subsection 20(4) of O. Reg. 490/09), regardless of worker participation in the medical surveillance program.

Worker participation in medical surveillance for designated substances is voluntary and on consent of the worker (subsection 28(3) of the OHSA). Once offered, a worker’s consent or refusal to participate in the medical surveillance should be documented by the employer.

Clauses 26(1)(i) and 26(1)(j) of the OHSA (which refer to prescribed medical examinations, tests or x-rays) pertain to medical examinations that deem a worker fit to work for safety reasons, such as in the mining and diving regulations. It does not apply to medical surveillance for designated substances.

Who can conduct medical surveillance examinations

Under the Code, an examining physician may be:

  • a company doctor
  • a private medical consultant contracted for by the employer
  • a physician on the staff of a clinic whose services are used by the employer
  • a worker’s own physician

Even if a worker’s own physician performs the surveillance, the employer must pay the costs specified in the regulation.

Qualifications to perform medical examinations for designated substances

In accordance with the Code, physicians conducting medical examinations and/or supervising clinical tests of a worker must be competent to do so because of knowledge, training and experience in occupational medicine.

Non-physicians

The Code and the Regulation are both written with reference to the term “physician”, and the Code specifies that this should be a physician with knowledge, experience and training in occupational medicine. The delegation of any part of the medical examination should be done in accordance with the applicable regulatory health professional colleges’ policies on delegation of controlled acts.

Paying only for clinical tests and an interpretation of these tests

If the employer is only offering clinical tests for designated substances to workers, the employer is not meeting their legal obligation to establish a medical surveillance program for the benefit of workers.

The components of a medical surveillance program for designated substances must include all of the components specified in the Code.

The examining physician is responsible for determining fitness to work in the case of exposure to a designated substance, based on the results of all the relevant components of the medical examination, including clinical tests.

Medical surveillance examinations

Information the employer should provide to physicians

In accordance with section 27 of O. Reg. 490/09, the employer shall provide a copy of a worker’s personal exposure record to the physician who examines the worker or supervises the clinical tests on a worker.

This record should include:

  • an identification of the worker, including the worker’s date of birth
  • the worker’s job(s) or occupation(s) at the workplace
  • results of monitoring the worker’s exposure to airborne concentrations of the designated substance
  • the time-weighted average exposure of the worker to the designated substance
  • the use of a respirator by the worker and its type
  • with respect to isocyanates other than those listed in Table 1 of O. Reg. 490/09, personal records of the length of time a worker is exposed to the isocyanates, among other information

See the guide to designated substances in the workplace for more information about employer responsibilities.

The examining physician can use the information provided in the personal exposure record to determine if a physical examination is required after the pre-placement medical examination. The information can also assist the examining physician in interpreting the results of the clinical tests.

Components of medical surveillance examinations

The requirements for the medical examinations for any of the 7 designated substances that are specified in the Code include:

  • a medical and occupational history, including:
    • frequency and duration of exposure to the designated substance
    • signs and symptoms that may be an early indication of health effects of exposure to the designated substance
  • a physical examination with particular attention to the systems that may be affected by the designated substance at pre-placement and as required for the other types of medical examinations
  • provision of health information on the designated substance
  • clinical tests that are specific to each designated substance

The focus of the components of the medical examination will vary depending on the designated substance in question and the timing of the medical examination (pre-placement, periodic, acute exposure or exit).

When to conduct medical surveillance examinations

Medical examinations are conducted:

  • at pre-placement for workers in jobs involving exposure to any of the 7 designated substances
  • at periodic intervals for any of the 7 designated substances
  • after an acute exposure to benzene, isocyanates, lead and mercury
  • when a worker leaves their placement working in exposure to any of the 7 designated substances, unless the most recent medical examination was performed within a certain period of time

The frequency of medical examinations including clinical tests vary depending on the designated substance.

Physicians are reminded that if a worker presents with signs and symptoms that require investigation this no longer constitutes medical surveillance, since the purpose of medical surveillance is to identify early changes to workers’ health in the absence of symptoms or signs of illness. A worker with signs and symptoms should see their treating health care professional for further assessment.

Respiratory questionnaires

The Code refers to a respiratory questionnaire, but does not specify which one. There may be questionnaires provided by medical specialty associations and other organizations that would be helpful or examining physicians can generate their own.

The intention of using a questionnaire is to ensure that there is a standard way of capturing subtle changes in symptoms and signs from examination to examination whereby physical examinations and clinical tests do not otherwise reveal any obvious changes.

When to conduct an acute exposure medical examination

The term “acute exposure” is not defined in the Code. It is a provision that allows for examining physicians to perform examinations in the intervals between periodic exams for benzene, isocyanates, lead and mercury when there has been an exposure incident otherwise not foreseen such as an accidental spill or failure of control measures.

The decision to perform an acute exposure medical examination is to be determined on a case-by case basis by the examining physician in consultation with the employer.

Unusually high exposures to designated substances

There are provisions in the Code for examining physicians to require more frequent medical examinations for heavier exposures or where there are changes in job tasks that may require additional medical surveillance.

There are no provisions in the Code for computerized tomography (CT) scans or other specialized tests (other testing modalities) to be included as a part of routine medical surveillance. The decision to perform earlier and/or more frequent testing should be made between the examining physician and the employer taking into consideration current best practices to follow in the circumstances.

Emerging best practices not in the current Code

As the Code is a minimum standard with minimum requirements, newer testing modalities may not be provided for under the Code.

Any decision to include newer testing modalities should be made between the examining physician and the employer. Questions about the Code and current best practices can be directed to the MLITSD Provincial Physician.

Information the physician must provide to the worker

At pre-placement and periodic medical examinations in respect of a designated substance, the examining physician must advise the worker of:

  • adverse health effects and symptoms associated with exposure to the designated substance, in the context of the individual worker’s health
  • the importance of notifying their employer if they are experiencing symptoms possibly resulting from exposure to the designated substance so that appropriate follow-up can be arranged (for example, review of control measures and referral for medical assessment)
  • the results of any clinical tests and if not available at the time of the medical examination, the process for ensuring that the worker is notified of the results when they become available
  • the importance of good personal hygiene practices in preventing exposures to the designated substance (for example, hand washing after working with the designated substance)
  • the hazards associated with eating or drinking in areas where there is the risk of exposure through ingestion of designated substances such as lead and mercury
  • the reproductive risks associated with exposure to certain designated substances such as lead and mercury
  • with respect to asbestos, coke oven emissions and silica, the harmful effects of smoking and exposure to the designated substance
  • non-occupational sources of exposure to the designated substance (for example, lead and the use of munitions) which may contribute to exposures

At an exit examination, a worker must be advised:

  • where appropriate, of the possible risks of future health effects associated with past exposures to the designated substance
  • to inform their personal physician (if different than the physician overseeing the medical surveillance) of their history of exposure to a designated substance and provide copies of their health records, as may be appropriate, to their personal physician
  • that further medical follow-up should be determined by their personal physician based on the worker’s individual risk profile, exposure history and current best practices

Clinical tests

Clinical tests are required as an additional indicator of the extent of a worker’s exposure to the designated substance. They are particularly useful in cases where:

  • knowledge of airborne concentrations of the substance alone may not ensure that a worker is not overexposed due to the possibility of exposure through another route (such as skin absorption, ingestion)
  • signs of overexposure or adverse effects are not detected on examination

Some clinical tests measure the concentration of the substance in a worker’s blood or urine, thus providing an indication of the amount that has been absorbed (such as lead). Other clinical tests are used to measure a specific function of the body (like lung function) that may be affected by exposure.

Pulmonary function tests and spirometric values cited in the Code

The Code refers to the term pulmonary function tests (PFTs), but for the purposes of medical surveillance, the only clinical tests for lung function required under the Code are values obtained from spirometry. The code cites the spirometric values FEV1 (forced expiratory volume in 1 second), FVC (forced vital capacity) and the FEV1/FVC ratio.

If the examining physician is of the opinion that a worker requires lung function measurements beyond those obtained through spirometry, the physician should discuss this with the employer.

Frequency of lung function tests required for asbestos, coke oven emissions and silica

The Code requires that a chest radiograph and lung function tests be done every 5 years after 10 years of exposure to certain designated substances (asbestos, coke oven emissions, and silica), or as required by the examining physician.

This frequency is appropriate for workers who are otherwise asymptomatic and show no signs of health effects from exposure to these designated substances. The Code allows an examining physician to increase the frequency of lung function tests if they have concerns that a worker’s health may be more acutely affected by exposure given the exposure records and history provided.

Standards for lung function tests

The Code does not specify the standard that an examining physician needs to follow for lung function tests. It is understood that physicians undertaking this work are familiar with current best practices for spirometry in the workplace at the time of the examination. This includes the requirements for maintenance and calibration of any equipment used, appropriate training and quality assurance of test procedures, and the interpretation of the test results.

Certification of individuals conducting lung function tests

O. Reg. 490/09 and the Code do not address certification requirements. It is up to the examining physician to ensure that any health care professional that is performing lung function tests has the required training and competence to do so.

Requesting more frequent medical examinations and clinical tests

An examining physician can request an increase in the frequency of medical examinations or clinical tests if they have concerns that a worker’s health may be more acutely affected by exposure to a designated substance, given the exposure records and history provided. This information can be communicated back to the employer by the examining physician along with the notification regarding fitness to work in exposure to a designated substance.

Action levels

The Code specifies “action levels” for the results of some clinical tests. When the test results are at these levels, action is called for, as detailed in the Code. Sometimes two action levels are specified:

  • a review (lower) level
  • a removal (higher) level

Interpreting the results of clinical tests with action levels

When the lower level (review level) is reached, the examining physician is required to review the following with an affected worker:

  • work practices
  • health status
  • personal hygiene practices
  • non-occupational sources of exposure to the designated substance

When the higher level (removal level) is reached — in some cases this result is confirmed by a second test — the worker must be removed from exposure to the designated substance until the test result drops to a permissible level for return to work, if applicable.

Where the results of clinical tests have not reached the action level or where there is no mandatory removal level, the examining physician may still advise that a worker is fit with limitations or unfit to continue working in exposure to a designated substance based on other signs of adverse health effects. In such a case, removal from exposure and return to the usual conditions of work are based on the judgement of the examining physician.

Other indicators to determine if a worker can remain at work

The use of action levels does not mean that clinical tests are intended to be the only indicator used to protect the health of workers. The examining physician must use professional judgement in discerning other signs of possible overexposure to the substance.

The clinical tests provide additional information that could indicate overexposure, and this is particularly important when signs of overexposure or adverse effects are not detected on examination, or the worker has a personal health condition that can influence the determination of fitness to work (such as pregnancy).

Conditional phase-in period for lead

The conditional phase-in period for workers participating in a medical surveillance program for inorganic lead was designed to allow a worker with a high body burden of lead to continue working in exposure to lead, in an environment with appropriate measures in place to control the exposure while allowing for ongoing reduction of the body burden of lead over time, and allowing for workplaces to revisit their current controls and make improvements as needed. This conditional phase-in period was included in the new Code requirements in January 2020 and expires January 1, 2025.

Determining fitness to work with designated substances

An assessment of a worker’s fitness to begin to work or continue to work in exposure to a designated substance is based on the results of the medical examination including the results of the clinical tests. This determination is a professional judgement that takes into consideration the requirements of the Code.

“Fit with limitations” and “unfit”

These determinations are made at the discretion of the examining physician and are a professional judgement based on:

  • the results of medical examinations including clinical tests
  • the requirements of the Code

A determination of being unfit refers specifically to whether or not a worker can continue working in exposure to a designated substance, but not an overall statement about their fitness to work.

Fit with limitations

In this case, the examining physician has concerns about the health effects of exposure to a designated substance and is making a medical recommendation that a worker continue working in exposure to a designated substance, but in a modified manner for a medical reason.

The worker can return to work in exposure to a designated substance, but with limitations specified by the examining physician (such as reduced hours, use of personal protective equipment not required by other workers).

The limitations:

  • may be both worker and designated substance specific
  • may include the need for more frequent testing if a clinical test is approaching an action level

Fitness to work has to do with the worker’s ability to continue working and the risk of ongoing health impacts from exposure to a designated substance. Any decisions around modifying the conditions of work (for example, the use of or a change in personal protective equipment) to allow for the worker to continue working should be considered “fit with limitations”. Such modifications may fail or prove to be inadequate, so these decisions should be reassessed regularly to ensure that the modifications are appropriate and to protect the worker from developing health effects from exposure to the designated substance.

Unfit

In this case, the examining physician makes a determination that a worker cannot continue to work in exposure to a designated substance.

For some designated substances, the Code sets out guidance and/or specifies action levels that can be used in making this determination.

Examples include:

  • a clinical test result that exceeds an action limit
  • confirmed sensitization to isocyanates
  • the examining physician’s opinion that any further exposure to a designated substance is contraindicated

Fitness in the case of pneumoconioses from exposure to asbestos or silica

In 澳门永利 the determination of whether a worker is considered unfit to work because of exposure to asbestos or silica is made at the discretion of the examining physician and should take into consideration the risk of disease progression with further work in exposure to the designated substance.

Determining if a worker can return to work

Determining if a worker can return to work in exposure to a designated substance after being found unfit to work in exposure to that designated substance depends on the substance.

For some designated substances (such as lead and mercury), a reduction to or below specific levels for clinical tests must be met prior to a worker’s return to work in exposure to the designated substance.

For other designated substances, a worker’s return to work in exposure to a designated substance is to be determined:

  • on a case-by-case basis by the examining physician
  • in consultation with a specialist educated and experienced in the practice of evaluation of the work-related illness in question
  • after careful review of sources of exposure and protective measures in the workplace to ensure worker exposure to the designated substance is minimized and below acceptable limits

Situations where a worker cannot return to work

In some cases, a worker cannot be returned to work in exposure to a designated substance. For example, a worker who is determined to have respiratory or skin sensitization to isocyanates should not have any further exposure to isocyanates.

Non-occupational sources of exposure and removal criteria

If a worker has non-occupational sources of exposure, whether they need to be removed according to the removal criteria needs to be determined on a case-by-case basis.

If a worker is working in exposure to a designated substance at work, also has non-occupational sources of exposure and their health has been affected by exposure at work or elsewhere, the examining physician needs to determine if they are fit to continue working in exposure to that designated substance knowing that they have evidence of such cumulative health effects from both types of sources.

If a worker exceeds the Code’s removal levels

If the results of clinical tests exceed the Code’s action level for removal of the worker from exposure, the examining physician is advised to deem a worker unfit to continue working in exposure to the designated substance until that worker’s level drops below the return-to-work level, and there has been a careful review of sources of exposure and implementation of protective measures in the workplace to ensure worker exposure is minimized and within acceptable levels.

Where the results of clinical tests have not reached the action level for removal, the examining physician may exercise professional judgement and still advise that a worker is unfit based on other signs of adverse health effects.

Notification and confidentiality

Notifying the worker and the worker’s employer

The examining physician who conducts the medical examination or supervises the clinical tests must advise the worker and the worker’s employer whether:

  • the worker has an occupational illness because of exposure to a designated substance
  • the worker is fit, fit with limitations or unfit to continue working in exposure to the designated substance

This advice must be provided without giving or disclosing to the employer the records, the results of the examination or clinical tests or the diagnosis, if any. The worker’s employer must act in accordance with the advice provided by the examining physician.

Notifying the joint health and safety committee

The examining physician who advises the worker and the worker’s employer that the worker is fit with limitations or unfit to continue working in exposure to a designated substance shall also advise the joint health and safety committee, in writing and on a confidential basis, and in giving the advice shall indicate their opinion as to the interpretation to be placed on the advice.

Notifying the Provincial Physician

The examining physician who advises the worker and the worker’s employer that the worker is fit with limitations or unfit to continue working in exposure to a designated substance shall also promptly communicate that advice to the Ministry of Labour, Immigration, Training and Skills Development (MLITSD) Provincial Physician.

The Provincial Physician can be contacted by email, mail or phone:

  • Phone: Toll-free: 1-877-202-0008 through the MLITSD Health and Safety Contact Centre
  • Email: MLITSD.Provincial.Physician@ontario.ca
  • Mail:   
    澳门永利 Ministry of Labour, Immigration, Training and Skills Development
    c/o Provincial Physician  
    Occupational Health and Safety Branch
    505 University Avenue, 19th Floor  
    Toronto, ON   
    M7A 1T7

After notification

After receiving a determination that a worker is fit with limitations or unfit to continue working in exposure to a designated substance, the Provincial Physician may advise MLITSD staff responsible for enforcement at that workplace, who may conduct a field visit to that workplace to ensure compliance with the OHSA and the regulations.

Learn more about occupational health and safety inspections and investigations.

Role of the examining physician in advising the workplace

An examining physician examines workers and makes decisions around their fitness to work in exposure to designated substances. As part of this role, an examining physician may become aware of certain processes, jobs or areas of a workplace that appear to pose a particular concern for worker overexposure.

This information could be of help to the employer in determining how to improve the controls in the workplace. If an examining physician obtains information that could help employers, they may share a high-level summary of the results with the employer without identifying any particular worker and/or their medical information, unless workers have consented to the disclosure of health records specific to their participation in medical surveillance for a designated substance to their employer. It would be advisable that any high-level summary also be shared with the joint health and safety committee as well.

It is ultimately the employer who is responsible for ensuring that their control program is working as intended, and that any changes to the controls in place are carried out to protect the health of workers. They may rely upon specialized services such as occupational hygienists, engineers and safety professionals to assess ongoing exposures and suggest changes to the control program.

OHSA requirements for confidentiality of personal health information

In addition to obligations under other laws and professional codes of conduct, personal health information is protected under the OHSA.

Specifically, section 63(1)(f) of the OHSA states that:

Except for the purposes of this Act and the regulations or as required by law, no person shall disclose any information obtained in any medical examination, test or x-ray of a worker made or taken under this Act except in a form calculated to prevent the information from being identified with a particular person or case.

Also, section 63(2) of the OHSA states that:

No employer shall seek to gain access, except by an order of the court or other tribunal or in order to comply with another statue, to a health record concerning a worker without the worker’s written consent.

Recordkeeping

The examining physician must keep records of medical examinations and clinical tests of workers, along with the personal exposure records of workers that have been provided by the employer.

These records are to be kept for 40 years from the date the first record was made or for 20 years from the date the last record was made, whichever is longer.

Records the examining physician can no longer retain

If an examining physician ceases to be able or willing to keep the records they must be forwarded to the Ministry of Labour, Immigration, Training and Skills Development (MLITSD) Provincial Physician who must keep the records in accordance with the above timelines.

Records of medical surveillance for designated substances and regular medical records

It is up to the examining physician to decide whether to separate the two types of records or not. The examining physician must fulfil the record retention requirements for both types of records. These requirements may be different for the two types of records and it is possible that the two types of records may be disposed of after different periods of time.

Requests for copies

A worker may request that the examining physician provide the worker or the worker’s physician with a copy of the worker’s personal exposure records and the results of the examinations including clinical tests. If the worker has died, the records may be released to the next of kin or the worker’s personal representative, upon written request. A physician who receives such a request shall comply with the request.