Page:NIOSH Manual of Analytical Methods - Chapter R.pdf/5

 '''TABLE 2. U.S. AND U.K. GUIDELINES AND LIMITS FOR OCCUPATIONAL EXPOSURE TO CRYSTALLINE SILICA.'''

Adapted from Hearl [24].

* Identified by NIOSH as a potential occupational carcinogen [16].

† See this website for sample calculations of the OSHA PEL: http://www.osha-slc.gov/SLTC/silica_advisor/ mainpage.html. Other useful information is available on this website: http://www.osha-slc.gov/SLTC/ silicacrystalline/rosem/index.html. On this web page, click on "Frequently Asked Questions."

CFR = Code of Federal Regulations; REL = recommended exposure limit; PEL = permissible exposure limit; TWA = timeweighted average; RDS = respirable dust standard; MRE = Mining Research Establishment (United Kingdom); TLV = threshold limit value; MEL = maximum exposure limit.

Under the OSHA Hazard Communication Standard (HCS) materials containing 0.1% or more crystalline silica by weight must follow federal guidelines concerning hazard communication and worker training [6, 8, 16]. Although HCS does not require the analysis of materials for crystalline silica content, material suppliers or employers may want to have materials analyzed for crystalline silica to be exempt from HCS requirements. Unfortunately, laboratories may need to deal with clients that assume a low concentration of a commonly occurring mineral like crystalline silica can be measured reliably and accurately. Sample inhomogeneity, measurement sensitivity and specificity limitations when other minerals are present make it difficult if not impossible for a laboratory to provide the conclusive evidence that laboratory clients seek to avoid HCS requirements. 3/15/03