Most employers do not need to keep a specific workplace temperature under federal Occupational Safety and Health Administration (OSHA) regulations. An employer with workers exposed to high temperatures should establish a complete heat illness prevention program.Provide workers with water, rest and shade. This new regulation goes into effect immediately. For current information about heat emergencies or places to stay cool in Contra Costa County, visit contracosta.ca.gov. Contra Costa Health supports businesses of all industries with the permits, regulations and processes they need to follow. Arnold Schwarzenegger on Tuesday announced emergency orders requiring water and shade for laborers who fall ill in the searing heat. CalOSHA does cover farmworkers. And California has extended protections on wages and working hours to both farmworkers and domestic workers. The areas with complete covereage are listed in black. California.