{"data":{"id":"us/30-cfr-57.8531","jurisdiction":"us","citation":"30 CFR 57.8531","heading":"Construction and maintenance of ventilation doors.","body":"Ventilation doors shall be—\n(a) Substantially constructed;\n(b) Covered with fire-retardant material, if constructed of wood;\n(c) Maintained in good condition;\n(d) Self-closing, if manually operated; and\n(e) Equipped with audible or visual warning devices, if mechanically operated.","path":["Title 30—Mineral Resources","CHAPTER I—MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR","SUBCHAPTER K—METAL AND NONMETAL MINE SAFETY AND HEALTH","PART 57—SAFETY AND HEALTH STANDARDS—UNDERGROUND METAL AND NONMETAL MINES","Subpart G—Ventilation"],"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":"58fff2ed082ab8f9fd3d53e79c01358490ecf10a2576760b73b1d6bac0286fbb","source_id":"us-cfr","stale":true,"prev":"us/30-cfr-57.8529","next":"us/30-cfr-57.8532"},"notice":"GroundRules: Original legal text. Not legal advice."}