Employer Responsibility

Employers must determine employee exposure measurements from breathing zone air samples representing the 8-hour time weighted average (TWA) and 30-minute short-term exposures for each employee.

Employers must take one or more samples representing full-shift exposure to determine the 8-hour TWA exposure in each work area. To determine short-term employee exposures, one or more samples must be taken to represent 30-minute exposures for the operations most likely to expose employees above the excursion limit in each work area.

They must also allow affected employees and their designated representatives to observe any employee exposure monitoring. When observation requires entry into a regulated area, they must provide and require the use of protective clothing and equipment.

For Class I and II jobs, employers must conduct monitoring daily that is representative of each employee working in a regulated area, unless they have produced a negative exposure assessment for the entire operation and nothing has changed. When all employees use supplied-air respirators operated in positive-pressure mode, daily monitoring may be discontinued. When employees perform Class I work using control methods not recommended in the standard, daily monitoring must be continued even when employees use supplied-air respirators.

For operations other than Class I and II, employers must monitor all work where exposures can possibly exceed the permissible exposure limits (PEL) often enough to validate the exposure prediction.

If periodic monitoring shows that certain employee exposures are below the 8-hour time weighted average (TWA), PEL, and the short-term exposure limit (STEL), the employee exposure monitoring is no longer required.

Changes in processes, control equipment, personnel, or work practices that could result in new or additional exposures above the 8-hour TWA, PEL, or STEL require additional monitoring regardless of a previous negative exposure assessment for a specific job.

The employer must, as soon as possible but no later than 5 working days after the receipt of the results of any monitoring performed under this section, notify each affected employee of these results either individually in writing or by posting the results in an appropriate location that is accessible to employees.

The employer must provide affected employees and their designated representatives an opportunity to observe any monitoring of employee exposure to asbestos conducted in accordance with this section.

When observation of the monitoring of employee exposure to asbestos requires entry into an area where the use of protective clothing or equipment is required, the observer must be provided with and be required to use such clothing and equipment and must comply with all other applicable safety and health procedures.

To learn more about Construction Asbestos Safety visit our Construction Asbestos Safety Online Training web page.