On September 30, the Maryland Occupational Safety and Health (MOSH) Division of Labor’s heat injury and illness prevention standard took effect, marking Maryland as the sixth state to issue a workplace safety standard designed to protect workers exposed to extreme heat in the workplace. Concurrently, the federal Occupational Safety and Health Administration (OSHA) is going through its notice-and-comment rulemaking process to implement a federal heat injury and illness standard. The federal standard is currently only a proposed rule, with comments from interested stakeholders due on December 30, 2024.

MOSH Heat Injury and Illness Standard

Under the MOSH heat standard, all workplaces in the state – with limited exceptions – where employees are exposed to heat indexes that equal or exceed 80°F will need to comply, regardless of whether the work is performed in an indoor or outdoor workplace. Notably, the regulation excludes emergency operations and essential services, incidental exposures where employees are exposed to the heat threshold for less than fifteen consecutive minutes over an hour, or in buildings, structures, and vehicles that have mechanical ventilation systems or fans that keep the heat index below 80°F.

The standard defines the heat index as “a measure of how hot it feels when relative humidity is taken into account along with the actual air temperature, which can be extrapolated from temperature and relative humidity using the National Weather Service Heat Index Calculator.” Covered employers under the MOSH standard will be required to monitor the heat index in the workplace using prescribed methods, including direct measurement of the temperature and humidity in the workplace, use of local weather data supported by the National Weather Service or other recognized sources, or use the National Institute for Occupational Safety and Health’s (NIOSH) Heat Safety Tool application. If the workplace does not have a mechanical ventilation system, employers are required to directly measure the temperature and humidity at the same time and location as employees are working.

After determining that their employees are exposed to heat at or above 80°F, employers must develop and maintain written Heat-Related Illness Prevention and Management Plans made available and accessible to their employees and MOSH upon request. These plans must include information regarding how cool, clean drinking water will be provided to employees, how to recognize signs and symptoms of heat-related illness (including heat exhaustion and heat stroke), response procedures to suspected heat-related illnesses, how employees will be provided sufficient breaks in shaded or cool, climate-controlled areas, how employers will implement rest break schedules, and procedures for “high heat conditions,” among other provisions. The regulation also mandates employers take preventive measures to protect workers, including providing shaded areas to exposed employees “as close to the work area as practicable,” providing at least 32 ounces of drinking water per hour to each exposed employee per work day, and acclimatization protocols for a period of up to 14 days for new or returning workers who have been absent from the workplace for seven days or more. The employer must set an acclimatization schedule that gradually increases exposure over a 5-14 day period with a maximum 20% exposure increase per day, uses the current National Institute for Occupations Safety and Health’s recommendations for acclimatization, or uses a combination of gradual introduction and alternative cooling and control measures. During this acclimatization period, employers must monitor the employees for signs of heat-related illness through regular communication via phone or radio, a buddy system, or other effective means of observation.

The standard also establishes a separate trigger for “high-heat conditions,” defined as a heat index at or above 90°F in the work area. When the heat index reaches “high-heat conditions,” employers must implement a work and rest schedule that’s “adjusted for environmental conditions, workload, and impact of required clothing or personal protective equipment.” Specifically, the rule requires employers to grant a minimum rest period of 10 minutes for every 2 hours worked when the heat index is above 90°F but below 100°F, and employers must provide at least 15 minutes of rest for every hour worked when the heat index is above 100°F. The MOSH standard specifies that employers may coincide rest periods with scheduled meal- and rest breaks.

The MOSH standard also requires employers to implement an emergency response plan should an employee exhibit signs and symptoms of heat-related illness. The plans must include procedures for ensuring effective and accessible means of communication at the worksite at all times that enable employees to contact a supervisor or emergency medical services, responding to signs and symptoms of heat-related illness, monitoring and providing care to employees exhibiting symptoms of heat-related illness, and contacting emergency medical services and transporting employees to those services if necessary.

In addition to the new requirements for employers when the workplace reaches certain temperatures, employees and supervisors must also receive training on work and environmental conditions before their first exposure to heat. This training must include personal risk factors that affect heat-related illness, the importance of drinking water and rest breaks, signs and symptoms of heat-related illness, first aid and emergency response measures, and the employer’s Heat-Related Illness Prevention and Management Plan, among other things. Employees must also receive additional training annually and immediately following any heat-related incidents at the worksite. Employers must maintain training records, including the names of those trained, dates of the training sessions, and a summary of the sessions’ content for one year from the date on which training occurred.

For more information on the Heat Standard and resources provided by MOSH visit the Maryland Department of Labor website.

Federal OSHA Heat Standard

As mentioned above, federal OSHA is currently undergoing the notice-and-comment rulemaking process for its own heat injury and illness prevention standard. The proposed rule was officially published in the Federal Register on August 30 and includes many similar provisions, such as developing plans, heat triggers, acclimatization protocols, and training requirements, to the Maryland OSHA heat standard described above. Generally speaking, the proposed rule mandates that employers implement heat injury and illness prevention plans, monitor workplace temperatures, take preventive measures to protect workers from heat-related injury and illness, have emergency response procedures in place if a worker experiences heat-related injury or illness symptoms, and provide training to workers, among other provisions.

Federal OSHA approves and monitors State Plans like MOSH so long as their standards are at least as effective as OSHA standards in protecting workers from work-related injuries, illnesses, and death. Given that the MOSH heat standard is substantially similar to the federal OSHA proposed rule, Maryland employers will not need to comply with the specific requirements of the federal OSHA rule; instead, Maryland employers will need to implement all required changes as directed under the MOSH standard. TCIA will continue to monitor for any updates related to state efforts and federal OSHA’s proposed rule to implement heat injury and illness regulations.