Climate Impacts on Farmworkers: Studies on Heat Stress & Night Work

Posted on Wednesday, April 3rd, 2019 by Renata Brillinger
Photo from UCDavis Western Center for Agricultural Health and Safety

The following two blogs excerpted below were recently posted by the Western Center for Agricultural Health and Safety (WCAHS), both related to the impacts of increasingly intense and frequent heat events on farmworker health and working conditions. 

California Heat Illness Prevention Study Findings

Click here for the full blog.

Avoidable deaths and heat-related illnesses still occur among California farmworkers despite regulations from the California Occupational Safety and Health Administration (Cal/OSHA) and a campaign to encourage drinking more water and taking more rests in the shade. The California Heat Illness Prevention Study (CHIPS) aimed to provide new data to quantify the physiological and behavioral risk factors for heat related illness (HRI) and develop the findings to produce more effective workplace strategies to reduce risk. As summers are predicted to become increasingly hot, the conclusions and translation of findings from this study will only become more important to the 800,000 farmworkers in California.

Physical Indicators of Heat Illness

CHIPS was the first study to collect comprehensive physiological data to monitor HRI, including core body temperature and the intensity of work performed during a shift, from 587 individuals working on a wide range of farms throughout California. All the farms studied complied with Cal/OSHA HRI prevention regulations.

Nevertheless, nearly 8% of the workers were at risk of HRI (experienced a core body temperature ≥ 101.3°F) and 6.5% were at risk because their body temperature increased ≥ 2.7°F over a work shift. Of the workers who participated in the study: nearly 12% were dehydrated at the end of the day (lost water weight of ≥ 1.5% of body weight), over 12% suffered reversible acute kidney injury over the work day, and 50% said they had at some point experienced a heat illness symptom while working.

Men were more likely to suffer elevated core body temperature, especially those working piece rate (paid by units of production rather than by the hour), irrigating, or working multiple outdoor tasks per shift. 

The workers who performed tasks that were slower-paced and less physically demanding were at less risk of HRI. Risk increases with age as well as with the level of dehydration, while high body mass index (high body weight for height), clothing choice, and other modifiable factors did not affect the risk of HRI in the workers.

Preventative Behavior and the Effects on Economic Earnings

Focus groups held throughout the California Central Valley indicated that workers mostly know they should be drinking more and resting frequently in hot weather, but they are not following through on these protective measures. There are some cultural beliefs that need to be addressed (such as the possible negative effect of drinking cold water when a person is hot), but the main reason workers risk their heath is economic.

If workers stop work to drink more or visit the bathroom, they reduce their productivity. On the one hand, this will materially affect their earnings if they are being paid by the piece. On the other, there is concern for their job security as workers are very aware their employer wants to have workers who can maximize productivity, no matter how hot the weather. These two factors suggest that though employers may encourage workers to drink and rest, their employees may not respond to the offer.

This explains why the current regulations have not been as effective as hoped, and point to improvements in both worker training and management that will reduce the risk of heat illness. The main audience for the new information will be occupational safety and health professionals, employer and worker organizations, insurers, and regulators.

Read more about training methodologies and resources the WCAHS plans to produce.


Night Work: A Growing Trend in Western Agriculture?

Photo from UCDavis Western Center for Agricultural Health and Safety

Click here for the full blog.

Farming doesn’t stop just because the sun sets. Across the West, a variety of crops are harvested at night, such as wine grapes, tomatoes, onions, garlic, and corn. Harvest, equipment transportation, set up, and maintenance as well as field prep and repairs, irrigation work, and pesticide application are other activities done at night.

Night Work is Increasing

The general, unofficial consensus among a number of professionals involved in agriculture is that night work is increasing. Possible reasons include rising temperatures and heat illness prevention regulations, increasing labor shortages, product quality and taste preferences, time-sensitive harvests, and avoidance of pests.

“The area’s cool nights create better working conditions—not only is the temperature more tolerable, but bees and rattlesnakes stay away at night” explains Lino Bozzano, VP of Vineyard Operation, in the Laetitita Vineyard and Winery blog, “Why We Harvest Fruit At Night.” Head Winemaker, Eric Hickey adds that “grapes are firmer, making them easier to work with.” Currently, very little quantitative information is available on night work in agriculture, such as how many growers have adopted the practice, the kind of work being done at night versus the day, and how growers address nighttime health and safety risks.

Health and Safety Implications

While more growers may be adopting nighttime work, there is concern that insufficient awareness of the hazards associated with night work puts agricultural workers at risk. Many safety risks of night work in agriculture are the same as the risks of daytime work, but they may be exacerbated by night conditions, such as limited visibility due to poor lighting or fatigue due to the disruption of biological rhythms leading to trips, falls, or collisions. Other risks include greater exposure to nocturnal animals and even criminal activity if lighting is poor.

In a 2010 article in Ergonomics, WCAHS investigator, Fadi Fathallah, PhD, cautions that night workers “undergo an inversion of this ‘natural’ [circadian rhythm] cycle by sleeping during daylight hours and working during night or dark hours. This disruption in the internal timing system and the physiological maladaptation to an inverted schedule can result in a variety of health and performance problems in workers, [such as] reduced quality of sleep, increased risk of cardiovascular disease, gastrointestinal disorders, reproductive dysfunction in women, and an increase in fatigue-related accidents.”

Night shift work has been shown in construction and hospital work to negatively affect health, including interruption of hormone release cycles, low immune response, cardiovascular disease, and miscarriage. The disruption of family life and social activities can lead to poor diet, stress, and lack of exercise. This is especially true if workers are picking up a second shift or working longer hours.

Next Steps

WCAHS is working to define specific research questions that can shed light on this issue so that both growers and workers can safely benefit from the change in traditional work hours.

Answering the questions of how and why night work is increasing will likely have significance for labor, agriculture, and health policy. WCAHS encourages investigators to apply for small grant funding from our center to explore these issues more deeply.

Read more here…

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