Supervisors and safety staff running outdoor crews in Washington — agriculture, construction, landscaping, and outdoor maintenance.
Washington L&I’s outdoor heat exposure rule triggers on plain air temperature, not WBGT, which makes it unusually easy to apply in the field: a thermometer is enough to know whether the rule has engaged. The state’s permanent wildfire-smoke rule (WAC 296-820) sits alongside it.
Which heat rule applies to this crew, today? In Washington the state's own standards are the enforceable floor — they are what an inspector cites. Above them sit the federal enforcement posture and the technical standards that contracts and site safety plans commonly adopt.
Declare the worksite as Washington in the calculator and the composite narrows to exactly this set: a rule binds only where it governs, so Washington's rules bind here and another state's do not. Rules from elsewhere are still evaluated and shown, marked advisory.
Washington’s permanent wildfire-smoke rule (WAC 296-820) supersedes the earlier emergency rule (WAC 296-62-085) and is PM2.5-canonical. Notification and voluntary respirator use engage at 20.5 µg/m³ — the lowest first divider of the three western states — exposure controls and voluntary N95 use at 35.5 µg/m³, a mandatory full respiratory protection programme at 500.4 µg/m³, and respirators with an assigned protection factor of 25 or greater at 555.0 µg/m³.
Legal status below is the registry's own legalStatus field for each rule. A "mandatory regulation" is enforceable law in its jurisdiction; everything else is guidance, a technical standard, or a proposal, and binds you only if your contract, your client, or your own programme adopts it.
Derived from the registry: every standard declaring US-WA. Wildfire smoke, where the state has a rule, is listed separately below — it is a different hazard axis and never enters the work/rest composite.
| Rule | Authority | Legal status | What it sets |
|---|---|---|---|
| Washington State DOSH Outdoor Heat Standard (WAC 296-62-095) | Washington State Department of Labor & Industries (L&I/DOSH) | Mandatory regulation | Work/rest limits |
These apply, or are cited, in Washington as anywhere else in the US. Full national picture: United States country page.
| Rule | Authority | Legal status | What it sets |
|---|---|---|---|
| OSHA Heat National Emphasis Program (CPL 03-00-024, April 2026) | US OSHA, Directorate of Enforcement Programs | Guidance — voluntary | Alert levels |
| OSHA Federal Heat Rule NPRM (Proposed) | US OSHA | Proposed rule — not yet enforceable | Control measures |
| NIOSH 2016-106 Table 6-2 | NIOSH | Guidance — voluntary | Work/rest limits |
| NIOSH REL/RAL Logarithmic Curve | NIOSH | Guidance — voluntary | Screening thresholds |
| ACGIH TLV / Action Limit | ACGIH | Technical standard — not law unless adopted or incorporated | Work/rest limits |
| La Isla Network-informed RSH-s Default Protocol | La Isla Network / Adelante Initiative | Industry guidance — voluntary | Work/rest limits |
Wildfire smoke is a separate hazard axis from heat. It is tracked as its own smoke_overlay rule type and is never folded into the work/rest composite above — full respirator thresholds, including the EPA 2024 PM2.5 breakpoints, are on the wildfire smoke guidance page.
| Rule | Authority | Legal status | What it sets |
|---|---|---|---|
| Washington L&I / DOSH Wildfire Smoke Rule (WAC 296-820) | Washington State Department of Labor & Industries (L&I/DOSH) | Mandatory regulation | Wildfire smoke thresholds |
An orchard crew in eastern Washington on a dry 38°C afternoon (100.4°F) at 20% relative humidity, with a site WBGT of 29°C, moderate work, and an acclimatized crew. Washington’s rule reads the thermometer directly, which is why it engages at a temperature the WBGT-keyed standards read as less severe — dry air suppresses WBGT but not the air temperature the rule is written against.
Inputs: air temperature 38°C · 20% relative humidity · WBGT 29°C · moderate work (300 W) · acclimatized worker · worksite declared in US-WA
| Rule | What it returns at these inputs |
|---|---|
| Washington State DOSH Outdoor Heat Standard (WAC 296-62-095) | 45 / 15 min work/rest per hr |
| La Isla Network-informed RSH-s Default Protocol | 45 / 15 min work/rest per hr |
| ACGIH TLV / Action Limit | 45 / 15 min work/rest per hr |
| NIOSH REL/RAL Logarithmic Curve | 28.2°C limit — exceeded |
Answer for this shift: 45 / 15 min work/rest per hr (most protective)
Every value above is computed at build time by the same engine the live calculator runs — the single most protective applicable result, never an average across standards. Change any input and the answer changes, which is what the calculator is for.
Screening-level guidance. This tool provides screening-level heat guidance for planning. It is a decision-support instrument, not a sole compliance authority or a medical prescription. Verify against the governing standard for your jurisdiction and consult a qualified professional for individual medical decisions.