437-002-1056 Exposure Assessment This rule requires an evaluation of employee exposure to silica using air monitoring or objective data as described in the performance or scheduled monitoring options. (1) Except for the specific conditions allowed for in 437-002-1057, assess the exposure of each employee who is or may reasonably be expected to be exposed to respirable crystalline silica at or above the action level in accordance with either the performance option in paragraph (2) or the scheduled monitoring option in paragraph (3). (2) Performance option. Assess the 8-hour TWA exposure for each employee on the basis of any combination of air monitoring data or objective data sufficient to accurately characterize employee exposures to respirable crystalline silica. (3) Scheduled monitoring option. (a) Perform initial monitoring to assess the 8-hour TWA exposure for each employee on the basis of one or more personal breathing zone air samples that reflect the exposures of employees on each shift, for each job classification, in each work area. Where several employees perform the same tasks on the same shift and in the same work area, you may sample a representative fraction of these employees in order to meet this requirement. In representative sampling, sample the employee(s) who are expected to have the highest exposure to respirable crystalline silica. (b) If initial monitoring indicates that employee exposures are below the action level, you may discontinue monitoring for those employees whose exposures are represented by such monitoring. (c) Where the most recent exposure monitoring indicates that employee exposures are at or above the action level but at or below the PEL, repeat such monitoring within six months of the most recent monitoring. (d) Where the most recent exposure monitoring indicates that employee exposures are above the PEL, repeat such monitoring within three months of the most recent monitoring. (e) Where the most recent (non-initial) exposure monitoring indicates that employee exposures are below the action level, repeat such monitoring within six months of the most recent monitoring until two consecutive measurements, taken 7 or more days apart, are below the action level, at which time you may discontinue monitoring for those employees whose exposures are represented by such monitoring, except as otherwise provided in paragraph (4). (4) Reassessment of exposures. Reassess exposures whenever a change in the production, process, control equipment, personnel, or work practices may reasonably be expected to result in new or additional exposures at or above the action level, or when there is any reason to believe that new or additional exposures at or above the action level have occurred. (5) Methods of sample analysis. Ensure that all samples taken to satisfy the monitoring requirements of this rule are evaluated by a laboratory that analyzes air samples for respirable crystalline silica in accordance with the procedures in Appendix A to this rule. (6) Employee notification of assessment results. (a) Individually notify each affected employee in writing of the results of that assessment or post the results in an appropriate location accessible to all affected employees in accordance with the following: (A) Construction employers with a NAICS code of 23 must notify affected employees within 5 working days after receiving any results an exposure assessment in accordance with this rule. (B) All other employers must notify affected employees within 15 working days after receiving any results of an exposure assessment in accordance with this rule. (b) Whenever an exposure assessment indicates that employee exposure is above the PEL, describe in the written notification the corrective action being taken to reduce employee exposure to or below the PEL. (7) Observation of monitoring. (a) Where air monitoring is performed to comply with the requirements of this rule, provide affected employees or their designated representatives an opportunity to observe any monitoring of employee exposure to respirable crystalline silica. (b) When observation of monitoring requires entry into an area where the use of protective clothing or equipment is required for any workplace hazard, provide the observer with protective clothing and equipment at no cost and ensure that the observer uses such clothing and equipment. Appendix. [ED. NOTE: Appendix referenced are available from the agency.] [ED. NOTE: To view attachments referenced in rule text, click here to view rule.] Statutory/Other Authority: ORS 654.025(2) & 656.726(4) Statutes/Other Implemented: ORS 654.001 - 654.295 History: OSHA 5-2016, f. 9-23-16, cert. ef. 7-1-18