30 CFR § 90.100 - Respirable dust standard.
---
identifier: "/us/cfr/t30/s90.100"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "30 CFR § 90.100 - Respirable dust standard."
title_number: 30
title_name: "Mineral Resources"
section_number: "90.100"
section_name: "Respirable dust standard."
chapter_name: "MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR"
subchapter_number: "O"
subchapter_name: "COAL MINE SAFETY AND HEALTH"
part_number: "90"
part_name: "MANDATORY HEALTH STANDARDS—COAL MINERS WHO HAVE EVIDENCE OF THE DEVELOPMENT OF PNEUMOCONIOSIS"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "30 U.S.C. 811, 813(h), 957."
regulatory_source: "45 FR 80769, Dec. 5, 1980, unless otherwise noted."
cfr_part: "90"
---
# 90.100 Respirable dust standard.
The following is required as of April 14, 2025. After the 20th calendar day following receipt of notification from MSHA that a part 90 miner is employed at the mine, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere during each shift to which the part 90 miner in the active workings of the mine is exposed, as measured with an approved sampling device and expressed in terms of an equivalent concentration, at or below 0.5 mg/m
<sup>3</sup>.
[89 FR 28482, Apr. 18, 2024]