Audit, Compliance and Risk Blog

Washington revises heat protection rules

Posted by Jon Elliott on Fri, Aug 04, 2023

pexels-edgar-toro-12222682 copyThis summer is again bringing record-breaking heat to parts of North America. Outdoor work in the summer sun can lead to heat illness, as can indoor work in spaces that aren’t sufficiently insulated or cooled. Since 2008, Washington state has required employer actions to protect employees from extreme heat during summer months, through rules administered by the Department of Labor & Industries’ (L&I’s) Division of Occupational Safety and Health (I discussed the pre-2023 rules HERE). Effective July 17, 2023, L&I has updated its Outdoor Heat Exposures rules, revising and expanding the requirements and making them applicable year-round. The remainder of this note summarizes the changing requirements.

How Does Heat Cause Illness?

When someone works in a hot environment, their body must shed excess heat to maintain a stable internal temperature. This is accomplished mainly by circulating blood to the skin, and by sweating. This becomes less effective when the air temperature is close to or warmer than normal body temperature, and/or when the humidity is high enough to prevent effective evaporation. Even when it works, the worker’s body tends to heat up, and fluids and salts lost by sweating will have to be replaced.

Definitions of "heat-related illness" vary, but Washington’s is typical: " A medical condition resulting from the body's inability to cope with a particular heat load, and includes, but is not limited to, heat cramps, heat rash, heat exhaustion, fainting, and heat stroke." Recognizing that each individual’s body may respond differently to workplace conditions, professionals and regulators provide different guidance about conditions that should trigger explicit attention to the hazard, Washington focuses on “outdoor [work] environments,” which are defined as follows:

Outdoor environment. An environment where work activities are conducted outside. Work environments such as inside vehicle cabs, sheds, and tents or other structures may be considered an outdoor environment if the environmental factors affecting temperature are not managed by engineering controls. [the latest revisions remove a caveat that formerly provided: Construction activity is considered to be work in an indoor environment when performed inside a structure after the outside walls and roof are erected.”]

The latest revisions include the following new definition:

Risk factors for heat-related illness. Conditions that increase susceptibility for heat-related illness including:

(a) Environmental factors such as air temperature, relative humidity, air movement, radiant heat from the sun and other sources, conductive heat sources such as the ground;

(b) Workload (light, moderate, or heavy) and work duration;

(c) Personal protective equipment [PPE] and clothing worn by employees; and

(d) Personal factors such as age, medications, physical fitness, and pregnancy.”

  • When and where does Washington require actions?

Washington has required heat-related protective measures every summery since 2008 (WAC 296-62-095 through 296-62-09560, and 296-307-097 through 296-307-09760). Until now, L&I has applied specific rules from May 1 through September 30 each year, but the latest revisions remove those calendar limitations to apply the rules year-round in recognition that hot weather can occur at other times. The revisions also amend the target temperatures above which employers must provide heat illness protections, to:

    • 52o F if employees are wearing ‘nonbreathable” clothes, including vapor barrier clothing or PPE (such as chemical resistant suits)”, or
    • 80o F for all other clothing

These new thresholds replace the prior applicability, which was 89 oF for most situations, 77 oF for workers wearing “double-layer woven clothes including coveralls, jackets and sweatshirts”, and 52 oF for workers wearing “nonbreathing clothes” (including vapor barrier clothing or PPE). The revised rules continue to exclude situations where exposures are limited to “incidental exposure” for no more than 15 minutes per hour.

  • What actions are required?

Heat illness can be prevented if workers have the chance to keep their body temperatures down, to cool off if they start to overheat, and to rehydrate. L&I requires Washington employers to implement an Outdoor Heat Exposure Safety Program, reflected in their state-mandated employer’s Accident Prevention Program (APP; similar to nationally recommended programs I discussed HERE). Effective with the latest revisions, employers’ Outdoor Heat Exposure Safety Programs must include at least the following when temperatures are at or above the thresholds identified above:

  • Procedures to provide at least one quart per hour of “sufficiently cool” drinking water (this term is not defined);
  • Encourage employees to frequently consume water or other acceptable beverages (such as electrolyte-replenishing beverages) to ensure hydration
  • Procedures for providing shade or other sufficient means to reduce body temperature, including the location of such means and how employees can access them;
  • Encourage and allow employees to take a preventative cooldown rest period when they feel the need to do so to protect themselves from overheating, using sufficient means to reduce body temperature (e.g., shade). This period must be paid unless taken during a meal period that is not otherwise compensated. If an employee shows signs or symptoms of heat-related illness during the cool-down rest period, the employer must relieve them of duty until recovered;
  • The specific method used by the employer to closely observe employees for signs and symptoms of heat-related illness;
  • Procedures for “close observation” for 14 days, of newly-assigned employees or when temperatures first meet threshold levels
  • Emergency response procedures for employees demonstrating signs or symptoms of heat-related illness;
  • Acclimatization methods and procedures;
  • High heat procedures (see below); and
  • Ensure that copies of the Program are available to employees and their representatives;

The latest revision adds additional requirements for High Heat Procedures when the air temperature is at or above 90o F (unless ameliorated by engineering or administrative controls such as air conditioning):

  • Ensure that employees take mandatory cool-down rest periods of at least
    • 10 minutes every 2 hours if temperature is at or above 90o F
    • 15 minutes every hour if temperature is at or above 100o F
  • Closely observe employees for signs and symptoms of heat-related illness, and provide a buddy system, or regular cell phone or similar communication for employees working alone (or comparable methods)

Employers must also provide employee training at least annually, consisting of

  • environmental factors and other work conditions that contribute to the risk of heat-related illness;
  • general awareness of personal factors that may increase susceptibility to heat-related illness (such as age, degree of acclimatization, medical conditions, drinking water consumption, and use of alcohol, caffeine, nicotine, and medications)
  • importance of removing heat-retaining personal protective equipment such as nonbreathable chemical resistant clothing during all breaks;
  • importance of frequent consumption of small quantities of drinking water or other acceptable beverages;
  • importance of acclimatization;
  • different types of heat-related illness, the common signs and symptoms of heat-related illness
  • importance of immediately reporting signs or symptoms of heat-related illness in either themselves or in co-workers to the person in charge, and procedures the employee must follow including appropriate emergency response procedures
  • importance of preventative cool-down periods (new requirement)
  • High Heat definition and associated additional procedures (new requirement)
  • Employer’s procedures for providing shade and other cool-down measures (new requirement)
  • Employer’s procedures for “close observation” of employees for signs and symptoms (new requirement)

Employers must also provide supervisor employee training, consisting of

  • the information required in the employee training listed above
  • procedures the supervisor must follow to implement applicable provisions of these rules, including routine requirements and incident response

In addition, the L&I regulations also make employees responsible for monitoring their own condition, including drinking water and using shade and other available preventative and restorative measures.

Now what?

These requirements are in place in Washington as of this writing. If your organization has outdoor workers in Washington, it must comply with the requirements identified above– note that they now apply year-round rather than just during summer months. Non-Washington employers should at least consider them as guidelines for use in evaluating protections against heat – similar requirements also exist in California, and the US federal Occupational Safety and Health Administration (OSHA) and most state OSH programs provide guidance to employers and their workers (I’ve written about heat illness prevention provisions several times, including HERE). Canadian occupational health and safety agencies also recognize “thermal stress” as a workplace hazard, with attention to both heat and cold.

Self-Assessment Checklist

Do any of my organization's workers work in situations where ambient heat may create a hazard of heat illness:

  • Outdoors (e.g., agricultural or construction work)?
  • Indoors (e.g., work in manufacturing or other processes involving hot materials or equipment)?

If so, does the organization provide appropriate:

  • Training (tailored to the workplace source(s) of heat hazards, preventive measures, and responses to heat illness?
  • Water?
  • Shade or other appropriate ways for workers to cool down?
  • Planning and procedures?

Does the organization include assessment of outdoor heat and wildfire hazards in the design and construction of new facilities, and in structuring of work activities?

Where Can I Go For More Information?

  • Washington L&I

- “Be Heat Smart” webpage 

- Revised rules (mark-up version) 

  • OSHA

- “Heat” webpage

  • Canada 

- Employment and Social Development Canada “Thermal stress in the work place” webpage 

- Canadian Centre for Occupational Health and Safety (CCOHS) “Hot Environments - Health Effects and First Aid” webpage 

- CCOHS “Forest Fires and Wildfire smoke” webpage

About the Author

jon_f_elliottJon Elliott is President of Touchstone Environmental and has been a major contributor to STP’s product range for over 30 years. 

Mr. Elliott has a diverse educational background. In addition to his Juris Doctor (University of California, Boalt Hall School of Law, 1981), he holds a Master of Public Policy (Goldman School of Public Policy [GSPP], UC Berkeley, 1980), and a Bachelor of Science in Mechanical Engineering (Princeton University, 1977).

Mr. Elliott is active in professional and community organizations. In addition, he is a past chairman of the Board of Directors of the GSPP Alumni Association, and past member of the Executive Committee of the State Bar of California's Environmental Law Section (including past chair of its Legislative Committee).

You may contact Mr. Elliott directly at:

Tags: Protecting employees, Heat, Be Heat Smart, heat illness, Labor & Industries