STANDARDS PRESENTATION Page 5 of 19 TO
CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD
TITLE 8 , DIVISION 1 , CHAPTER 4
( A ) The employer shall 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 , on the same material and in the same work area , the employer may sample a representative fraction of these employees in order to meet this requirement . In representative sampling , the employer shall 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 , the employer may discontinue monitoring for those employees whose exposures are represented by such monitoring . However , monitoring shall not be discontinued for high-exposure trigger tasks , which shall be monitored at least every 12 months or more frequently as required in this section .
( C ) Where the most recent exposure monitoring indicates that employee exposures are at or above the action level but at or below the PEL , the employer shall 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 , the employer shall 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 , the employer shall 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 the employer may discontinue monitoring for those employees whose exposures are represented by such monitoring , except as otherwise provided in subsection ( d )( 4 ). However , monitoring shall not be discontinued for high-exposure trigger tasks , which shall be monitored at least every 12 months or more frequently as required in this section .
( 4 ) Reassessment of exposures . The employer shall 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 the employer has any reason to believe that new or additional exposures at or above the action level have occurred .
( 5 ) Methods of sample analysis . The employer shall ensure that all samples taken to satisfy the monitoring requirements of subsection ( d ) are evaluated by a laboratory that analyzes
OSHSB-98 ( 2 / 98 )