{"data":{"id":"us/30-cfr-60.2","jurisdiction":"us","citation":"30 CFR 60.2","heading":"Definitions.","body":"The following definitions apply in this part:\nAction level means an airborne concentration of respirable crystalline silica of 25 micrograms per cubic meter of air (µg/m 3) for a full-shift exposure, calculated as an 8-hour time-weighted average (TWA).\nRespirable crystalline silica means quartz, cristobalite, and/or tridymite contained in airborne particles that are determined to be respirable by a sampling device designed to meet the characteristics for respirable-particle-size-selective samplers that conform to the International Organization for Standardization (ISO) 7708:1995: Air Quality—Particle Size Fraction Definitions for Health-Related Sampling.\nSpecialist means an American Board-Certified Specialist in Pulmonary Disease or an American Board-Certified Specialist in Occupational Medicine.","path":["Title 30—Mineral Resources","CHAPTER I—MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR","SUBCHAPTER M—UNIFORM MINE HEALTH REGULATIONS","PART 60—RESPIRABLE CRYSTALLINE SILICA"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-30.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:25:24Z","sha256":"1a1030999cf4e5ce32a9e79321f3334746088c106f1c11e66e6bac41321f1114","source_id":"us-cfr","stale":true,"prev":"us/30-cfr-60.1","next":"us/30-cfr-60.10"},"notice":"GroundRules: Original legal text. Not legal advice."}