1.5 Measuring Chemical Exposure
1.5.1 Determination of the Need for Exposure Measurements
The vast majority of chemicals used in research laboratories, when used in research quantities, do not pose a significant health hazard if SOPs and good laboratory hygiene practices are employed. Laboratory staff must not be exposed to OSHA regulated substances above permissible exposure limits. An exposure assessment, performed by EH&S, is designed to evaluate the chemical(s) used in terms of its concentration and quantity, frequency of use, manner in which it is used along with the available engineering controls, in an effort to determine the potential exposure to a user. An exposure assessment will be accompanied by recommendations on methods to reduce exposure, where exposure may exist, and will typically follow the hierarchy of controls (see Section 1.4). The exposure assessment is an important component of the CHP in protecting University employees from potential exposure to hazardous substances.
1.5.2 Exposure Assessment Strategy
EH&S utilizes information from various sources to develop its exposure assessment strategy, including laboratory chemical inventories (see Section 1.2.2), laboratory safety surveys, chemical purchase records, and chemical waste identification. Exposure assessments are carefully planned and coordinated with laboratory personnel to ensure that work activities representative of the exposure potential being assessed are being performed during the assessment. Laboratory hygiene practices will be reviewed and may be qualified and/or quantified with surface wipe sampling and analysis. Personal and area air sampling/monitoring studies may be used to quantify the airborne concentration of a hazardous substance, since inhalation is typically the primary route of concern for exposure to hazardous chemicals. The results of the assessment will be reviewed and evaluated in comparison to accepted Occupational Exposure Limits (OELs).
1.5.3 Frequency of Exposure Measurements
As noted in Section 1.5.2, an initial exposure assessment may include personal air sampling, with samples collected in the employee’s breathing zone to represent an employee’s exposure during a full shift [e.g., 8-hour time weighted average (TWA)] and/or 15 minute Short-Term Exposure Limit (STEL). EH&S will consult with laboratory personnel to determine which groups of employees have potential exposure to establish similar exposure groups (SEGs) so representative exposure samples can be collected.
Depending on the results of the exposure assessment, monitoring may need to be repeated, as required by OSHA or determined EH&S. An exposure assessment may also be repeated if the laboratory makes a substantive change (i.e., change in chemicals, equipment and/or control measures) to the process under which a prior exposure assessment was performed. If substantive changes do occur, laboratory personnel must contact EH&S for a re-evaluation. Additionally, an exposure assessment may be repeated at the request of an employee or when any employee reports signs or symptoms of exposure. EH&S will advise the laboratory when exposure monitoring can be discontinued.
1.5.4 Notification of Exposure Measurement Results
EH&S will provide a report of the exposure assessment within 15 days of receiving exposure assessment results. If the results are below the accepted OELs, the PI or laboratory supervisor will be notified and asked to post results in the laboratory and/or inform affected employee(s) of the results. If the results are above the accepted OEL, the affected employee(s) and PI and/or laboratory supervisor will be notified and asked to meet with EH&S to discuss the results and next steps, which may include enrollment in a medical surveillance program.