This pilot, seeks to characterize the burden of heat-related illness in Washington State agriculture, potential risk factors for heat-related illness, and methods for quantifying the physiological effects of heat exposures on agricultural workers.
Heat exposure has been identified as an important cause of non-fatal illness and death in agricultural workers. From 2003 to 2008, the U.S. Agriculture, Fishing, and Forestry sector experienced the highest mean heat fatality rate, with the majority of these fatalities occurring in relatively young workers in the crop production and support subsectors. Few studies have focused on heat-related Illness (HRI) in hired crop workers, who are largely seasonal, foreign-born, and Spanish-speaking. Likewise, there is limited research on how cultural beliefs and practices related to hydration and HRI may affect the prevention and treatment of HRI in these workers. This study characterizes the burden of HRI in Washington State agriculture, potential risk factors for HRI, and methods for quantifying the physiological effects of heat exposure in agricultural workers.
Principal Investigator: June Spector, MD, MPH
Associate Professor, Environmental and Occupational Health Sciences
University of Washington
University of Washington
This two-year pilot found that 1) farmworkers subscribe to varying degrees to the belief that cooling treatments should be avoided after heat exposure; 2) the desire to lose weight may be reflected in behaviors that promote increased sweating; 3) highly caffeinated energy drinks are preferred to increase work efficiency and maintain alertness; and 4) the location of drinking water at work (e.g., next to restrooms) and whether water is clean are important considerations for worker consumption of drinking water. Risk factors found to significantly contribute to HRI for the participants of a field survey of 97 workers included: younger age (and less work experience), piece rate pay, and longer distances to the toilet.
This study generated baseline data and set the stage for the future study of the association between potential HRI risk factors and heat effects as well as the development of interventions to reduce HRI. In the new cycle from 2016-2021, Dr. Spector began a new project entitled, A Multi-level Approach to Heat-Related Illness Prevention in Agricultural Workers.
Aim 1. Investigate cultural beliefs and practices related to hydration and HRI in adult outdoor crop workers.
Aim 2. Identify potential HRI risk factors in adult outdoor crop workers.
Aim 3. Measure heat exposure and physiological responses (heat strain) in the fields in a sample of adult outdoor crop workers.
Partners and Advisories
Washington State Department of Labor & Industries’ SHARP Program
Spector J. T., Krenz J., Calkins M., Ryan D., Carmona J., Pan M., Zemke A., Sampson P. D. Associations between heat exposure, vigilance, and balance performance in summer tree fruit harvesters. PMCID: PMC5912891Appl Ergon. 2018 Feb;67:1-8. doi: 10.1016/j.apergo.2017.09.002. Epub 2017 Sep 15. PubMed PMID: 29122180; PMCID: PMC5912891.
Quiller G., Krenz J., Ebi K., Hess J. J., Fenske R. A., Sampson P. D., Pan M., Spector J. T. Heat exposure and productivity in orchards: Implications for climate change research. Arch Environ Occup Health. 2017 Nov 2;72(6):313-316. doi: 10.1080/19338244. 2017.1288077. Epub 2017 Jan 31. PubMed PMID: 28139172; PMCID: PMC5562533.
Spector J. T., Bonauto D. K., Sheppard L., Busch-Isaksen T., Calkins M., Adams D., Lieblich M., Fenske R. A. A Case-Crossover Study of Heat Exposure and Injury Risk in Outdoor Agricultural Workers. PLoS One. 2016 Oct 7;11(10):e0164498. doi: 10.1371/journal.pone.0164498. eCollection 2016. PubMed PMID: 27716794; PMCID: PMC5055365.
Spector J. T., Krenz J., Blank K. N. Risk Factors for Heat-Related Illness in Washington Crop Workers. J Agromedicine. 2015; 20(3):349-59. doi: 10.1080/1059924X.2015.1047107. Epub 2015 Aug 3. PubMed PMID: 26237726; PubMed Central PMCID: PMC5562231.
Spector J. T., Sheffield P. E. Re-evaluating occupational heat stress in a changing climate. Ann Occup Hyg. 2014 Oct;58(8): 936-42. doi: 10.1093/annhyg/meu073. Epub 2014 Sep 26. PubMed PMID: 25261455; PMCID: PMC4481564.
Spector J. T., Krenz J., Rauser E., Bonauto D. K. Heat-related illness in Washington State agriculture and forestry sectors. Am J Ind Med. 2014 Aug;57(8):881-95. doi: 10.1002/ajim.22357. Epub 2014 Jun 20. PubMed PMID: 24953344; PMCID: PMC5562230.
Lam M., Krenz J., Palmández P., Negrete M., Perla M., Murphy-Robinson H., Spector J. T. Identification of barriers to the prevention and treatment of heat-related illness in Latino farmworkers using activity-oriented, participatory rural appraisal focus group methods. BMC Public Health. 2013 Oct 24;13:1004. doi: 10.1186/1471-2458-13-1004. PubMed PMID: 24156496; PMCID: PMC4015616.
Software: Spector J & Lieblich M. (2016) R package to estimate wet bulb globe temperature from datasets of standard meteorological measurements using models developed by Liljegren et al. Version 1.0. Available at:
Training: Preventing Heat-related Illness (HRI). Agricultural Medicine in the Northwest: Special Topics Lecture Series. CDC accredited CME is available to those who complete this course. To view the course flyer, click here. To proceed to
complimentary registration, click here.
Trade article: Avoiding heat-related illness - Study finds workers paid piece rate tend to work harder and take fewer breaks, increasing the risk of heat-related illness symptoms. Good Fruit Grower Dec 28, 2015.