The Schwarzenegger administration called for the action following what are believed to be heat-related deaths of a handful of farm workers earlier this summer.
The new regulations require employers to educate supervisors and workers about heat stroke and take other precautions according to Renee Bacchini of the California Department of Industrial Relations.
"Things like shade for employees who are feeling ill from the sun. Enough water, four cups per hour, per employee."
Marc Grossman of the United Farm Workers Union praised the administration for taking action.
"An emergency regulation was the only way that farm workers in the Central Valley would have some protection during this hot summer harvest season this year."
Employers who don't adhere to the regulations are subject to criminal prosecution.