(1) General. Each employer who has a workplace or work operation covered by this section must determine the 8-hour TWA exposure for each employee exposed to chromium (VI). This determination must be made in accordance with either subsection (2) or (3) of this section.

(2) Scheduled monitoring option.

(a) The employer must perform initial monitoring to determine the 8-hour TWA exposure for each employee on the basis of a sufficient number of personal breathing zone air samples to accurately characterize full shift exposure on each shift, for each job classification, in each work area. Where an employer does representative sampling instead of sampling all employees in order to meet this requirement, the employer must sample the employee(s) expected to have the highest chromium (VI) exposures.

(b) If initial monitoring indicates that employee exposures are below the action level, the employer may discontinue monitoring for those employees whose exposures are represented by such monitoring.

(c) If monitoring reveals employee exposures to be at or above the action level, the employer must perform periodic monitoring at least every six months.

(d) If monitoring reveals employee exposures to be above the PEL, the employer must perform periodic monitoring at least every three months.

(e) If periodic monitoring indicates that employee exposures are below the action level, and the result is confirmed by the result of another monitoring taken at least seven days later, the employer may discontinue the monitoring for those employees whose exposures are represented by such monitoring.

(f) The employer must perform additional monitoring when there has been any change in the production process, raw materials, equipment, personnel, work practices, or control methods that may result in new or additional exposures to chromium (VI), or when the employer has any reason to believe that new or additional exposures have occurred.

(3) Performance-oriented option. The employer must determine the 8-hour TWA exposure for each employee on the basis of any combination of air monitoring data, historical monitoring data, or objective data sufficient to accurately characterize employee exposure to chromium (VI).

(4) Employee notification of determination results.

(a) In general industry within five work days after making an exposure determination in accordance with subsection (2) or (3) of this section, the employer must individually notify each affected employee in writing of the results of that determination or post the results in an appropriate location accessible to all affected employees.

(b) In construction and shipyards, marine terminals, and longshoring within five work days after making an exposure determination in accordance with subsection (2) or (3) of this section, the employer must individually notify each affected employee in writing of the results of that determination or post the results in an appropriate location accessible to all affected employees.

(c) Whenever the exposure determination indicates that employee exposure is above the PEL, the employer must describe in the written notification the corrective action being taken to reduce employee exposure to or below the PEL.

(5) Accuracy of measurement. Where air monitoring is performed to comply with the requirements of this section, the employer must use a method of monitoring and analysis that can measure chromium (VI) to within an accuracy of plus or minus twenty-five percent and can produce accurate measurements to within a statistical confidence level of ninety-five percent for airborne concentrations at or above the action level.

(6) Observation of monitoring.

(a) Where air monitoring is performed to comply with the requirements of this section, the employer must provide affected employees or their designated representatives an opportunity to observe any monitoring of employee exposure to chromium (VI).

(b) When observation of monitoring requires entry into an area where the use of protective clothing or equipment is required, the employer must provide the observer with clothing and equipment and must ensure that the observer uses such clothing and equipment and complies with all other applicable safety and health procedures.