EXPOSURE ASSESSMENTS, MONITORING AND MEDICAL CONSULTATION
Hazard assessments are conducted to identify the hazards and general controls for work environments where workers may have physical or chemical exposures. These assessments can be performed by the line management or an ES&H professional. Hazard assessments may precede Exposure Assessments are conducted by EH&S professionals to ensure that protective measures are implemented and to ensure worker health compliance with applicable regulations or other requirements. Exposure assessments are required prior to issuing and using respiratory protection equipment.
An exposure assessment is a more formal evaluation process performed and documented by EH&S professionals to determine the risk of personnel exposure to hazardous chemical, or physical agents, and the adequacy of hazard controls. Results of exposure assessments are used to validate or improve hazard controls, to extend the same controls to employees with similar exposures, to provide employees with appropriate medical tests and examinations (i.e., medical surveillance) to monitor employee health, and to demonstrate compliance with regulations. Pub 3000, Chapter 32, “Job Hazards Analysis,” describes this process in more detail.
Exposure assessments may be either qualitative or quantitative assessments of risk. Qualitative exposure assessments result from observation and the use of professional judgment, whereas quantitative assessments involve conducting measurements (i.e., Exposure Monitoring) or by estimating or modeling of exposures.
The main type of exposure monitoring is personal air sampling. There are other techniques that can assist in determining employee chemical risk, including Area air sampling, dermal exposure assessment, wipe sampling and bulk sampling (see definitions.. Not all chemical contaminants have established analytical methods; however, those that do may be monitored by:
- Personal air sampling: Air is sampled from a worker’s breathing zone and analyzed to determine the presence and concentration of airborne contaminants,
- Area air sampling: Air concentrations of an agent are collected in a specified area to determine whether it meets an established criterion. This method is most often used after a clean up or remediation operation, such as lead or asbestos,
- Dermal monitoring: A technique used to assess a worker’s skin exposure to a given chemical. This strategy is used for substances that have properties that may allow them to cross the intact skin into a worker’s system,
- Wipe sampling: Surfaces (such as bench tops) are tested to determine the presence and amounts of residual contaminants on surfaces, and
- Bulk sampling: Materials are collected and analyzed to determine the presence and amounts of contaminants such as lead and asbestos. These are normally collected before demolition, construction and renovation activities.
Employee exposure to airborne chemicals will be kept at or below the occupational exposure limits referenced below. The potential for exposure to airborne chemicals is lower in laboratories than in industrial settings. This is because smaller quantities of chemicals are used, and they are normally handled in fume hoods or other systems, such as gloveboxes and workers have usually received advanced training. However, if there is reason to believe that use of a chemical may produce airborne levels above applicable limits (regardless of occupational setting) then air exposure monitoring will be conducted. If initial monitoring indicates exposures above one-half of the applicable limits, follow-up monitoring will be conducted. Moreover, controls (such as work practices, training, personal protective equipment, engineering, ongoing air monitoring and medical surveillance) will either be put into place or enhanced, based on the judgment of the Industrial Hygienist and any specific OSHA standard that may apply. Monitoring will be terminated when successive follow-up measurements indicate exposures are below one-half of the applicable Occupational Exposure Limit (OEL).
Exposure assessments are conducted by EH&S Industrial Hygienists and other EH&S professionals to identify the potential for employee exposure to hazardous materials and to ensure proper control measures are in place. These are done apart from the Job Hazard Analyses, which are performed by Work Leads or Supervisors. Exposure assessments may be conducted for operations involving the use of particularly hazardous substances, unstable/reactive compounds, chemicals regulated by OSHA substance specific standards, and for other chemicals and operations as deemed appropriate by an EH&S Industrial Hygienist. Exposure assessments may also be done in response to a Health Services referral, or when a concern is expressed by an employee, a supervisor, or a Work Lead.
Occupational Exposure Limits (OELs) and Interpretation of Monitoring Results
Air sampling results are compared to exposure limits to determine if the potential for hazardous exposure exists. The following occupational exposure limits are used:
- The OSHA 8-hour Time-Weighted Average Permissible Exposure Limit (PEL) for a substance. This is a legal exposure limit that must not be exceeded.
- The American Conference of Governmental Industrial Hygienists Threshold Limit Values (ACGIH TLV). These are intended as recommended 8-hour, Time-Weighted Average concentrations, though they are included in 10 CFR 851, the DOE Worker Safety and Health rule.
- The OSHA Action Level (AL). An AL, which is normally one-half the substance’s PEL, normally triggers additional monitoring and/or medical surveillance requirements.
- The OSHA and ACGIH Short-Term Exposure Limit (STEL) is the average concentration to which workers can be exposed for a short period of time (15 minutes) without suffering from irritation, chronic, or irreversible tissue damage or narcosis, provided that the daily 8-hour time-weighted average exposure limit is not exceeded. The STEL is intended to protect workers from acute toxic effects.
- OSHA and ACGIH Ceiling Limits (C). The concentration that may not be exceeded during any part of the working exposure (workday).
Several individual substances have both OSHA and ACGIH exposure limits. In some cases, the values of these two limits are different. In accordance with Berkeley Lab's Work Smart Standards, the lower of the two limits is used to interpret exposure results.
The OSHA exposure limits (29CFR1910 Subpart Z—Toxic and Hazardous Substances) are available online.
Various criteria exist for evaluating the results from wipe and bulk samples. Consult the Industrial Hygienist providing support to your Division for more information.
Employee Notification of Monitoring and Recordkeeping
The Industrial Hygienist conducting the exposure-monitoring shall give written notification of the monitoring results to the employee (and employee’s supervisor) in accordance with the specific OSHA requirements for that substance. Where no criterion exists, monitoring results will be provided within 15 days of receiving analytical results from the laboratory performing the analyses.
Health Services shall also be notified of exposure monitoring results.
Monitoring records will be managed by the Industrial Hygiene Group.
Medical Consultations and Examinations
Medical consultations and examinations related to employee exposure are provided by Health Services (ext. 6266) to any employee exposed at or above an Action Level (or in the absence of an established AL, one-half the lower of the OSHA PEL or the ACGIH TLV); when an employee develops a sign or symptom of exposure to a hazardous material; or when an uncontrolled event such as a spill, leak, or explosion takes place in which there is a likelihood of employee exposure. Anyone with a concern or question may request a medical consultation. Health Services should also be consulted by women who are either pregnant or intend on becoming pregnant.
Medical consultations and examinations will be conducted in accordance with Berkeley Lab’s Health Service Program policies and procedures, which are described in PUB-3000, Chapter 3; “Health Services.”