Chemical Exposure Monitoring (CEM) at the Workplace

Chemical exposure monitoring involves assessing the level of workers’ exposure to hazardous chemicals and evaluating the adequacy of existing control measures. Workers’ exposure to these chemicals through inhalation can be measured by conducting air monitoring.

Air monitoring is the process of quantifying or determining the identity of a chemical using standard sampling instruments, techniques, and strategies. A sampling device is employed to separate and collect the contaminant from a measured volume of the atmosphere.

The contaminant can be quantified instantaneously using direct reading instruments. Integrated air sampling instruments can be used to measure airborne hazardous chemicals according to validated methods. The chemical levels in the atmosphere are then established in terms of mass or number concentration for particulates, or volume concentration for gases and vapors.

What is Chemical Exposure Monitoring (CEM)?

Chemical exposure monitoring is a critical aspect of workplace safety, governed by the Occupational Safety and Health (Use and Standard of Exposure of Chemicals Hazardous to Health) Regulations 2000 (USECHH Regulations). These regulations define Chemicals Hazardous to Health (CHTH) as any chemical or preparation that is:

  1. Listed in Schedule I or II of the USECHH Regulations;
  2. Classified under any hazard class specified in the Health Hazards of the First Schedule of the Occupational Safety and Health (Classification, Labelling and Safety Data Sheet of Hazardous Chemicals) Regulations 2013 [P.U.(A) 310/2013] or as amended;
  3. Defined as a pesticide under the Pesticides Act 1974 [Act 149] or as amended; or
  4. Listed in the First Schedule of the Environmental Quality (Scheduled Wastes) Regulations 2005 [P.U. (A) 294/2005] or as amended.

The USECHH Regulations mandate that employers conduct a chemical health risk assessment (CHRA) for each work activity involving the use and exposure of CHTH to workers. This assessment must be carried out by an assessor who is appointed by the employer and registered with the Department of Occupational Safety and Health (DOSH).

One of the key responsibilities of the assessor is to determine the necessity of chemical exposure monitoring for each assessed work unit. Chemical exposure monitoring must be conducted under the USECHH Regulations when an assessment of health risk indicates that:

  1. Monitoring is required to ensure workers’ exposure does not exceed the Permissible Exposure Limit (PEL) or is maintained at the lowest practicable level; or
  2. Monitoring is necessary to ensure the adequacy of control measures for worker exposure to CHTH.

The PELs for CHTH are specified in Schedule I of the USECHH Regulations.

Purposes of Chemical Exposure Monitoring (CEM)
Generally, the purposes of air monitoring conducted at the workplace include:

  1. To help towards the design of exposure control measures and to evaluate the effectiveness of control measures;
  2. Evaluation of exposure level relative to an exposure limit;
  3. As periodic monitoring to meet regulatory requirements;
  4. Measurement of initial or baseline exposure data;
  5. Providing a historical record of worker’s exposures for company and worker’s records;
  6. Identification of potential overexposure situations or high-exposure activities; and
  7. Identification of contaminants in an emergency situation (such as a hazardous chemical spill), or in an unknown atmosphere (as in a confined space).

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How is Chemical Exposure Monitoring (CEM) Conducted?

The monitoring is conducted in accordance with the principles outlined in the guidelines established by the Department of Occupational Safety and Health (DOSH), specifically the “Guidelines on Monitoring of Airborne Chemical Hazardous to Health 2022.”

Below are the steps or methodologies taken during the monitoring.

A preliminary survey will be conducted to obtain a general overview of your workplace, including its layout and work operations. We will also identify the work area or work unit and the chemicals to be monitored.

The information that will be gathered includes:

  1. Health risk assessment
  2. Hazard information of the chemicals to be monitored
  3. Tasks carried out
  4. Task duration and frequency
  5. Work pattern and control measures in place, considering how these might affect exposures

Our HT will conduct the preliminary survey by walking through the work area with direct-reading instruments, if available, to observe work activities and trends of exposure, and to communicate with the employer and workers involved.

A group of workers subject to a similar degree of exposure is known as a “similar exposure group” (SEG). Based on this trait, we will identify an SEG in each work area or work unit where chemicals are to be monitored and divide the selected workers into SEGs.

The workers may be categorized according to the process, chemical, activity, equipment, task, and other relevant factors.

What is Similar Exposure Group (SEG)
Similar exposure group (SEG) refers to a group of workers who are assumed to have a similar degree of exposure. Generally, the size of SEG (number of workers constituting an SEG) will be considered in many cases to be three (3) or more.

There are some cases of an SEG having only one (1) or two (2) workers; conversely some large SEG consist of several tens of workers. For example, workers assigned to operate forklift in a warehouse may be grouped as having similar potential exposures to carbon monoxide.

For air monitoring purpose, the identified work unit may be considered as one (1) SEG or subdivided into a few SEGs depending on the variation of exposure. Then, selection of workers for monitoring will be randomly selected within the identified SEG.

Our HT will identify the appropriate sampling technique to conduct the air sampling, based on the physical state of the chemicals to be monitored.

There are two common methods for collecting samples:

  1. Integrated air sampling (active or passive)
  2. Direct reading or real-time monitoring sampling

Our HT will determine the monitoring strategy to be used in conducting the air sampling. This strategy includes deciding on the sampling duration, the number of sampling media required, and the number of workers to be sampled.

We will take at least three (3) samples for each chemical in each SEG to be monitored. If the number of workers is less than three (3), our HT will need to replicate the monitoring on another day or shift.

  1. The next steps will be based on the results of the three (3) samples, which are:
  2. If all three (3) results are less than 10% of the PEL, it can be assumed that the PEL is complied with, and we can proceed to the conclusion and recommendation of the monitoring; or
  3. If any result exceeds the PEL, the employer must improve control measures to reduce the exposure; or
  4. If any result is at or more than 10% of the PEL but at or below the PEL (0.1 PEL ≤ x ≤ PEL), our HT will take six (6) more samples for further analysis.

We will perform statistical analysis as outlined in Section 6.3 of the Guidelines on Monitoring of Airborne Chemical Hazardous to Health 2022.

Based on the monitoring results, we will compare them directly with the PEL to determine if any of the results exceed the PEL.

If the compliance test fails, we will recommend that the employer improve control measures to reduce exposure, focusing particularly on work practices or the enhancement of engineering control measures. Our HT may also review the sources of exposure and the efficiency of control measures using direct-reading instruments.

Our HT will conclude the results and then recommend actions to be taken by your organization based on the outcomes of the monitoring. If a work unit or work area fails a compliance test, we may recommend that the employer review and improve the existing control measures in that unit or area before conducting periodic monitoring.

Finally, we will prepare the monitoring report according to the outlined report writing format. The report will be presented and submitted to you within one (1) month after the completion of the monitoring.

Your organization can then make improvements based on the sampling results.

chemical exposure monitoring should be conducted to workers exposed to CHTH
An illustration of a laboratory worker exposed to hazardous airborne.

What are Included in the CEM Report?

The chemical exposure monitoring (CEM) report will be divided into several main sections, each containing core elements essential to the monitoring as per outlined by Chapter 7 – Report Writing of the guidelines. While the layout of the report may vary slightly between consultants and practitioners, this variation can be attributed to factors such as personal preferences, industry-specific best practices, and client requirements.

The core sections of the report are as follows:

The front page will contain the following information:

  1. The title of the report
  2. Type of monitoring (Area/Personal monitoring)
  3. Report reference number that contains hygiene technician’s name and competency registration number
  4. Place of monitoring – Name & address including DOSH registration number (if any)

The executive summary will contain a summary of the purpose, main activities, findings, recommendation and conclusions of the monitoring activity that has been conducted.

The introduction will consist the following information:

  1. Background information on the workplace, including a description of processes and work activities in the monitored area.
  2. If the monitoring is conducted in stages, differing from the chemical risk assessor’s recommendation, please specify and provide justification.
  3. Objective of the monitoring.
  4. Date of monitoring.
  5. Name of the hygiene technician and competency registration number.
  6. Number of shifts and number of workers for each work unit.

This section outlines the following information:

  1. Method used
  2. List of equipment used (serial number, calibration and expiry date)
  3. Type of sampling media used
  4. Selection of worker from Similar Exposure Group (SEG)
  5. Justification on monitoring duration and number of samples
  6. Type of monitoring (Personal or area)
  7. Statistical analysis tool used, if applicable

The result and finding of the monitoring will be presented as follows:

  1. Monitoring Area Information
  2. Monitoring Result (Personal/ Area)
  3. Descriptive Statistical Data and Compliance Test

This section outlines on the findings of the monitoring result and relates to:

  1. Compliance with PEL
  2. Factors contribute to the exposure such as work practice, standard operating procedures, unsafe act or unsafe condition
  3. Adequacy of existing control measures
  4. Justification on sampling strategy including its limitation such as limited samples, due to the nature of work activity or task frequency

Summary of the previous monitoring report should be included (if available). The summary should outline the recommendation of the monitoring which may include the following information:

  1. Result and finding
  2. Frequency of monitoring
  3. Compliance with PEL
  4. Adequacy of existing control measures
  5. Summary of recommendations

For the current monitoring report, our HT will provide recommendations and justifications which may include:

  1. Necessity of further monitoring
  2. Necessity to review the control measures
  3. Necessity of periodic exposure monitoring

This section outlines whether the monitoring objective is achieved and determine the workers exposure in compliance with the PEL. Most importantly, overall finding and action to be taken should be summarized in this report.

Lastly, all references should be included in the final section of the report which may include the followings:

  1. Copy of certificate of competency
  2. HT notification form (attached)
  3. Process flowchart
  4. Method Used (eg: US NIOSH Method)
  5. Calibration certificate
  6. Data and calculation form
  7. Certificate of Analysis from laboratory
  8. Plan layout with monitored workers location
  9. Descriptive statistics calculation and related data

Benefits of CEM to the Organization

Generally, conducting chemical exposure monitoring (CEM) of chemicals hazardous to health (CHTH) at the workplace offers several important benefits to your organization such as:

1. Protection of Worker Health
Chemical exposure monitoring helps identify hazardous chemicals in the workplace, allowing employers to take appropriate measures to mitigate risks. By monitoring exposure levels, employers can prevent adverse health effects such as respiratory problems, skin irritations, and long-term illnesses related to chemical exposure. Consequently, the monitoring enables the early detection of overexposure to harmful chemicals, allowing for timely intervention and reduction of health risks.

2. Compliance with Regulations
Chemical exposure monitoring also ensures compliance with Occupational Safety and Health (Use and Standards of Exposure of Chemicals Hazardous to Health) Regulations 2000 (USECHH Regulations) and other relevant legal requirements. Most importantly, regular monitoring helps employers avoid penalties and legal liabilities associated with non-compliance.

3. Improved Workplace Safety
Chemical exposure monitoring provides data for conducting health risk assessments, helping to identify high-risk areas and processes. Furthermore, the monitoring serves as vital opportunity for your organization to evaluate the effectiveness of existing control measures, such as ventilation systems and personal protective equipment (PPE), leading to improvements in workplace safety.

4. Informed Decision-Making
Chemical exposure monitoring provides accurate data on chemical exposure levels, enabling informed decision-making regarding safety protocols and control measures. Employers can use monitoring data to continuously improve workplace safety practices and reduce exposure risks.

5. Protection of Company Reputation
By conducting regular chemical exposure monitoring, companies demonstrate their commitment to employee safety and health, enhancing their reputation. A safe work environment builds trust with employees, customers, and stakeholders, leading to improved employee morale and business relationships.

6. Historical Exposure Records
Chemical exposure monitoring provides a historical record of workers’ exposure levels, which can be valuable for future reference and health assessments. In case of health claims or investigations, historical data can support the evaluation of exposure-related issues and protect your organization from false workers’ claim.

7. Optimization of Resources
Lastly, chemical exposure monitoring helps prioritize areas requiring intervention, ensuring that resources are allocated effectively to manage exposure risks. By identifying and mitigating risks early, companies can reduce costs associated with health care, absenteeism, and regulatory fines.

Chemical Exposure Monitoring (CEM) FAQs

Laboratory accredited under Skim Akreditasi Makmal Malaysia (SAMM) by Department of Standards Malaysia or any equivalent recognized international body.

Particles that are hazardous when deposited anywhere in the respiratory tract which the particle aerodynamic diameter is 100 micrometers (μm) and smaller.

Yes. Chemical exposure monitoring (CEM) is a further recommendation from the chemical health risk assessment (CHRA).

No. You can run your operation as usual. Indeed, we need to collect the samples based on your normal business operation and activities.

References

  1. Occupational Safety and Health Act (OSHA) 1994.
  2. Occupational Safety and Health (Use and Standards of Exposure of Chemicals Hazardous to Health) Regulations, 2000.
  3. Guidelines on Monitoring of Airborne Chemical Hazardous to Health 2022.