Maryland Occupational Safety and Health (MOSH) issued the final version of its Heat Stress Standards, which became effective on September 30, 2024, becoming the first state on the East Coast to adopt a heat standard and joining others such as California, Colorado, Minnesota, Oregon, and Washington in doing so. The standards take a sweeping approach to regulating heat injury and illness issues, requiring employers to develop heat-related illness prevention and management plans, monitor temperatures at worksites, train employees, and implement other measures such as breaks and acclimatization programs.
MOSH’s new heat standards apply to all “employer[s] with employees whose employment activities, indoor or outdoor, expose employees to a heat index in the area where the employee is working that equals or exceeds 80 degrees Fahrenheit.” This effectively covers anybody working outside in the summer as well as many indoor places of employment without air conditioning. While the proposed federal heat standard has the same heat threshold, even California’s standard does not apply indoors until the temperature exceeds 82 degrees Fahrenheit.
There are several notable exceptions to the standards’ broad scope, including incidental exposures of no more than 15 consecutive minutes per hour as well as in “[b]uildings, structures, and vehicles that have a mechanical ventilation system or fan that maintains the heat index below 80 degrees.”
When the 80-degree threshold is met, the standards generally require two things: heat monitoring and developing a heat illness prevention plan, which itself has many required components.
Heat index monitoring must be performed using one of three methods: (1) directly measuring temperature and humidity, (2) using local weather data from the National Weather Service or another recognized source, or (3) using the National Institute for Occupational Safety and Health’s (NIOSH’s) Heat Safety Tool. That being said, for employees working in buildings or structures without ventilation, employers are required to directly monitor the temperature and humidity in the area where the employees work, i.e., they cannot rely on local weather data or the NIOSH tool.
Employers must also develop, implement, and maintain a heat-related illness prevention and management plan. The plan must address hydration, rest, acclimatization, clothing and personal protective equipment, emergency response, and training, among other topics. The plan must be made accessible to employees and MOSH upon request.
MOSH’s heat standards require employer plans to cover a number of prevention measures after the heat thresholds are triggered:
Acclimatization. The MOSH heat standards require employers to provide for acclimatization for up to 14 days “[w]hen an employee is newly exposed to heat in the workplace” and “[w]hen an employee returns to work after 7 or more consecutive days of absence from the workplace.” Seven days is a particularly short window for the acclimatization requirement to be triggered and is even shorter than the proposed federal rule (14 days), effectively mandating that employees will need to acclimatize after vacation, illness, or leave that keeps them out of work for a week or more.
The acclimatization requirement includes developing and implementing a written acclimatization schedule, which must comply with one of three permissible methods, including gradually increasing exposure by no more than 20% over a 5- to 14-day period. Employers must also monitor employees during the acclimatization period for signs of heat illness.
Shade Access. Employers must provide shaded areas to exposed employees as close to their work area as practicable. Shaded areas must be outside, open on three sides, exposed to air, and large enough for the number of affected employees, among other requirements. If creating outdoor shade is demonstrably infeasible or unsafe in the work area, the employer must implement alternative cooling and control measures that provide equivalent protection to shade. Employers may also provide cooling with an indoor mechanical ventilation system as an alternative to outdoor shade.
Drinking Water. Employers must provide 32 oz. of drinking water per hour to each exposed employee, again as close to their work area as practicable.
Emergency Response. Employers must implement an emergency response plan. This plan must include procedures to ensure effective and accessible communication (i.e., to contact supervisors, 911, etc.), respond to signs of heat illness, monitor and care for employees with heat illness, and contact emergency medical services, as needed.
Training. Employers must provide training to employees and supervisors both initially, before first exposure to heat, and annually thereafter, as well as immediately following any heat illness incident. Training must cover the specific work environment and conditions, personal risk factors, and the importance of hydration and breaks, among other topics. Records of training must be maintained for one year and made available to MOSH upon request.
Beyond the 80-degree heat trigger, MOSH’s heat standards also require employers to implement special procedures for “high-heat” conditions when the heat index hits 90 degrees Fahrenheit. When these heat thresholds are met, employers must monitor employees for signs of heat illness and provide a 10-minute shaded rest period per two hours worked in 90- to 100-degree heat and a 15-minute shaded rest period per hour worked in 100-degree heat.
That said, these rest periods may coincide with other scheduled rest and meal periods. Employers may also choose to use alternative heat-control measures instead of the required rest periods so long as the alternative measures are effective, documented in writing, and readily available and accessible to employees at all times.
Unlike the California standard and proposed federal standard, the Maryland standard does not specify that breaks must be paid, although it does say that “[a]n employer may not discourage employees from taking rest breaks as needed to prevent heat-related illness.”
While MOSH’s heat standards technically became effective on September 30, 2024, in practice the cooler seasonal weather in Maryland likely gives employers until the spring to figure out compliance. In the interim, employers should begin preparing their heat-related illness prevention and management plans and implementing them, as necessary, to help address heat hazards and minimize enforcement risk when temperatures in Maryland rise again next year.
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