Washington — Increased enforcement of – and subsequent revisions to – California’s outdoor heat standard resulted in at least 33% fewer worker deaths, according to a recent study.
Researchers from George Washington University and Middlebury College looked at county-level data from 1999 to 2020 for California and neighboring states (Arizona, Nevada and Oregon).
The California heat standard was introduced as the first in the nation in 2005, but the researchers assert that it “was not actively enforced” by the state’s Division of Occupational Safety and Health until 2010.
They estimate that between 2010 and 2014, during a period of increased enforcement, the state experienced a 33% decrease in heat-related deaths among outdoor workers. Then, in 2015, California “closed loopholes” related to “water, rest and shade enforcement.” That led to an estimated 51% decrease in heat-related deaths over the six-year period ending in 2020.
“These findings demonstrate the urgent need for effective heat legislation at the national or state level to safeguard more workers against rising temperatures,” the researchers concluded. “Commonsense protections – water, shade and rest – are easy for management to execute and effective at improving worker health and safety.
“However, our results also highlight that policy implementation alone may be insufficient: California’s experience suggests that heat standards require robust enforcement mechanisms and well-designed regulations to achieve their protective potential.”
The study was published in the journal Health Affairs.



