The Massachusetts Department of Labor Standards (DLS) encourages employers to plan ahead to protect workers from excessive heat. California's Heat Illness Prevention Standard requires employers to provide training, water, shade, and planning.This standard applies to most workplaces where the indoor temperature reaches 82°F. It establishes required safety measures for indoor workplaces. Laws, regulations, cases, and both web and print sources on legal requirements for winter heat, and sources of assistance. The new regulation is triggered whenever employees are working indoors, and the temperature equals or exceeds 82 degrees Fahrenheit. What will be required under the new OSHA rule? The proposed standard is broad and covers all employers with employees working indoors or outdoors when the heat index is 80°F or higher. The Occupational Safety and Health Administration (OSHA) has no official rules or limits on temperature regulation in the workplace. Some states go above and beyond OSHA's regulations to protect employees from heat-related illnesses.