Agricultural fields in Davis, CA
Version en Español


California has the largest and most diverse agricultural production in the USA.  Cool coastal areas produce commodities year round, but warmer, drier inland valleys are made most productive with irrigation. The peak harvest season is summer and early fall when temperatures regularly exceed 90 °F (32 °C) and often are above 100°F (38 °C).  During these hot summer months many of the crops are hand harvested and require large numbers of agricultural laborers.  These laborers are mostly immigrant Latino workers, and the majority permanently reside in the USA. 


Despite a large quantity of information on the environmental and personal risk factors for heat-related illness (HRI), and California’s strict regulations concerning the protection of agricultural workers, deaths and HRI events continue to occur.

Most farmers and labor contractors now provide water, shade, bathrooms and HRI training for their workers, but a significant number of illnesses due to heat still happen each year. Some sectors have moved to night harvesting (for example vineyards), but this is not possible for many other commodities.

Although generally hot and dry in the summer throughout the state, the diversity of crops, tasks, and climate mean one ‘blanket’ rule on work conditions is not likely to be universally useful for training workers how to protect themselves.

The goal of the California Heat Illness Prevention Study (CHIPS) is to understand the physiological responses to environmental heat and physical work in inland valley field workers, and the socio-cultural influences that affect the workers’ behavior and therefore their risk of suffering HRI. Ultimately we want to use the study information to create improved HRI prevention strategies for both the employers and employees on farms.

Field work started in the summer of 2012 and will continue in the summers 2014-2016.

We wish to thank all the workers, farms and labor contractors who have already participated in our study. Our team enjoyed meeting and working with you all, and really appreciated your contributions!