Water Well Journal
Issue link: https://read.dmtmag.com/i/752472
Scope and application: The new Silica Rule applies to all occupational exposures to respirable crystalline silica in construction work, except where employee exposure will re- main below 25 micrograms per cubic meter (25 µg/m 3 ) of air. Permissible exposure limit: 50 µg/m 3 Action level: 25 µg/m 3 Exposure assessment: Any combination of exposure monitoring data or objective data may be used to accurately characterize exposures to crystalline silica. A reassessment of exposures is required whenever there has been a change in the production process, control equip- ment, personnel, or work practices that may reasonably be ex- pected to result in new or additional exposures to respirable crystalline silica at or above the action level (25 µg/m 3 ) At construction work sites, the employer is not required to assess the exposures of employees engaged in the tasks or take additional measures to ensure exposures do not exceed the permissible exposure limit (50 µg/m 3 ) where the employer has fully and properly implemented the engineering controls, work practices, and respiratory protection prescribed in the standard for specified tasks. Exposure monitoring: If the scheduled exposure moni- toring option is used to assess exposure, monitoring must be performed: • Initially • Every three months if greater than or equal to the permissible exposure limit • Every six months if greater than or equal to the action level. Discontinue if less than the action level, and subsequent exposure monitoring taken at least seven days later confirms exposure is less than the action level. Employee notification: Results of the exposure assess- ment must be posted, or each affected employee must be notified in writing, within: • Fifteen working days after completing an exposure assessment (general industry) • Five working days after completing an exposure assessment (construction). The employee notification must describe the corrective action being taken to reduce employee exposure to or below the permissible exposure limit. Written exposure control plan: Is required and must contain at least the following elements: • Description of the tasks involving exposure to respirable silica • Description of the engineering controls, work practices, and respiratory protection used to limit employee expo- sure to respirable crystalline silica for each task • Description of the housekeeping measures used to limit employee exposure to respirable crystalline silica • For construction work sites, a description of procedures used to restrict access to work areas, when necessary, must also be included to minimize the number of employees exposed to respirable crystalline silica and SAFETY from page 40 waterwelljournal.com 42 December 2016 WWJ