Farm Workers Help Design 4 New Heat Illness Prevention Videos


The California Heat Illness Prevention Study (CHIPS) is proud to present 4 new Spanish-language educational videos on:

  1.            Heat and Humidity Index
  2.            Importance of Water, Shade, and Rest
  3.            Symptoms of Heat Illness
  4.            What to Do In Case of an Emergency

The videos are each 2 to 3 minutes long and based on feedback from farm worker focus groups that said they would prefer watching short, informative videos on heat illness rather than receive written pamphlets.

The videos feature real farm workers and CHIPS staff acting out symptoms of heat illness, such as dizziness and fainting, while working in a field. The videos explain the first signs of heat illness and what to do, as well as the importance of drinking water instead of soda, energy drinks, coffee, and beer. Many workers are unaware that consuming these drinks to ‘cool down’ is actually counterproductive because they have high sugar levels and some drinks contain chemicals that give a false sense of energy (caffeine rush). The videos also explain what to do in an emergency.

At the end of each video, 3 short review questions are presented so viewers can review the information and supervisors can discuss the video with their workers.

You can access the videos at

Adjusting to Work in the Heat: Why Acclimatization Matters

UntitledThe joys of summer are here, but with them come the hazards of working in the heat. Acclimatization to heat is an important part of keeping safe as temperatures rise. This natural adaptation to the heat takes time, and from a management perspective, it may require careful planning.

Make acclimatization part of your plan

A good heat illness prevention plan takes into account the need for more breaks, a cool place to rest, the availability of fluids, and the careful allotment of time for a worker to become fully adjusted or acclimatized to the heat. It will need to be flexible based on the intensity of the heat, the level of humidity, the workers’ experience on the job, and the workers’ physical fitness.

Time to adapt

  • New workers on an 8-hour shift should spend only about an hour and a half in the heat on their first day. Their exposure time should increase slowly—no more than a 20% increase per day. Acclimatization depends on each person. It could take 10 days for some and up to 14 days for others.New Worker Acclimazation copy (1)
  • Experienced workers on an 8-hour shift should take about 4 days to acclimatize to the heat. They can spend up to 4 hours in the heat on the first hot day. The second day they can likely manage 5 hours in the heat and about 6.5 hours on the third day. By the fourth day, most healthy workers should be able to tolerate 8 hours in the heat assuming they are well hydrated and have appropriate rest breaks throughout their shift. However, a worker should always listen to how his/her body feels and take necessary precautions of hydration, rest, and shade.Experienced Worker Acclimazation copy (1)


Slide1Fluids are necessary for acclimatization. In fact, failure to replace the water lost in sweat will slow or even prevent the development of the physiologic adaptations to heat. Workers need to drink small amounts of water throughout the day so that they never become thirsty. For moderately intense work in moderate heat, this equates to approximately 1 cup every 15 to 20 minutes. Supervisors should encourage and remind workers to take water breaks. In some cases, when workers are experiencing heavy sweating, drinks containing electrolytes might be warranted.


In the heat, workers need more rest than they would in cooler environments. Provide a cooler place out of the direct sunlight where they can take their scheduled breaks. A shaded or air-conditioned rest area would be best. Air conditioning will not affect acclimatization. Remind and encourage workers that they need to take advantage of these rest breaks.

How does the body adapt?

When workers are initially exposed to hot work environments, they may readily show signs of distress and discomfort. Their core temperatures and heart rates increase. They may experience headaches, nausea, and other symptoms of heat-related illness. The brain’s thermoregulator detects the increases in skin, muscle, and organ temperature and ignites the body’s cooling mechanisms—primarily sweating and vasodilation of the skin’s blood vessels. As the body is exposed to the heat and is given proper recovery time, it begins to adapt. Many physiologic changes occur including an increase in total sweat capacity, sweating beginning at a lower skin temperature and conservation of body salt.

How should workers maintain these benefits?

A few days out of the heat won’t ruin a worker’s acclimatization, but absence from work in the heat for a week or more can result in a significant loss of those helpful adaptations. Upon return, the worker may combat acute dehydration, illness, or fatigue so supervisors need to make adjustments so the worker has time to re-acclimatize. This can take 2 to 3 days when returning to a hot job.

Planning for the heat requires extra care and effort. But a good heat illness prevention plan that allows workers to properly acclimatize will reduce the risk of heat-related illness and death. For more information, visit the NIOSH Topic Page on Heat Stress or the California Heat Illness Prevention Study (CHIPS), which is led by WCAHS investigators. You can read about a day in the life of the CHIPS workers studying heat illness in the agricultural fields.

This blog was first published by NIOSH on 14 July 2014 and adapted here for the WCAHS site.

How healthy is your California neighborhood?

You can easily find out using CalEnviroScreen, an online environmental health screening tool that scores each of the state’s 8000 census tracks for pollution burden and population characteristics.

Sacramento Business Portraits

Gina Solomon, Deputy Secretary for Science and Health, Cal EPA

Gina Solomon, Deputy Secretary for Science and Health at the California EPA, was a recent WCAHS seminar speaker and  explained that each California census tract has been scored for pollution burden and population indicators of environmental health. Pollution indicators include ozone, particulate matter, diesel, drinking water, pesticides, toxic releases, traffic, cleanups, and groundwater. Population characteristics include age, asthma, low birth weight, low education, linguistic isolation, poverty, and unemployment.

To see how your census track is doing,  click on the pollution burden or population characteristic map, find the particular census track you are interested in, and then click on an individual pollution indicator or population characteristic tab. Each census track is color coded. Darker colors indicate a greater score and relatively higher pollution burden / population vulnerability than areas with lighter colors and lower scores. For example, the pesticide burden for the City of Monterey is much less (light color) than the area surrounding the City of Salinas (dark color), which is heavily farmed and famous for fruits and vegetables.


CalEnviroScreen was created to help implement a state law (SB 535) requiring 25% of  proceeds from the state’s cap-and-trade auctions be invested in projects that benefit disadvantaged communities, including 10% for projects located within these areas. Thus, CalEnviroScreen allows the state to identify California communities with the greatest cumulative exposure to pollution and send state resources to those who need it most.

Lucky for us, CalEnviroScreen is also a great resource for public health researchers interested in a specific problem or location or how multiple environmental stressors affect a community. Dr. Solomon pointed out that many of California’s most disadvantaged communities are in rural, agricultural areas, and CalEnviroScreen can provide WCAHS researchers with a wealth of information.

WCAHS Celebrates California Ag Day 2016

How long does it take to adapt to high temperatures? That was one question on the trivia wheel that WCAHS brought to California Ag Day 2016 at the State Capitol on March 16th. The answer, by the way, is 2 – 14 days for the average person to acclimate to high heat.

2A. Leslie at CA Ag Day

Leslie Olivares with the heat illness trivia wheel.

California Ag Day is annual event that celebrates the abundance of California agriculture and its work force – the farmers, ranchers, laborers – and all that agriculture provides to our communities. Over forty exhibitors involved with all facets of state agriculture, including WCAHS Education and Outreach Specialist Teresa Andrews and Junior Specialist Leslie Olivares, step up tables on the west steps of the Capitol for the public to visit.

The popular WCAHS prize wheel focused on heat illness prevention, which is an especially relevant concern for farm workers, or anyone, spending long periods of time working outside during heat events in California. Children as well as adults were eager to spin the wheel to test their knowledge and win a prize.  The relaxed, family friendly event was a great way to promote our educational work and future training on heat illness.

WCAHS thanks California AgrAbility not only for the incredible work that they do for farm worker health, but also for graciously sharing their table with us. We were pleased to be part of California Ag Day and will attend similar outreach events in the coming months. For more information on these events, contact WCAHS at or (530) 752-5253.

Check out this California Department of Food and Agriculture YouTube video to learn more about the day.

Professional Dreams May Change, but the Overall Goal is Reached

IMG_1325Jose Gutierrez has made an incredibly positive impact at WCAHS since he first started as a student worker in 2010. Below he reflects on his various experiences at WCAHS before leaving for a new job as coordinator of Pasos Saludables – a farmworker wellness program – at Reiter Affiliated Companies, one of the world’s largest berry growers. Jose will be missed, but we are excited to see him continue his path in occupational health and safety!

How did you come to WCAHS?

I started as a student assistant in the office and later participated in some education and outreach activities. After I completed my B.S., I was hired as a Community Health Program Representative for WCAHS with a heat illness research project. My new duties included working with the databases and coordinating the team activities at the field during the summer. [Notes: Read and see pictures of the student research team in an earlier blog.]

Did your career goals change while at WCAHS?

Yes, I started out wanting to be a physician and majored in Biopsychology and Spanish. When I was introduced to the “research world” I loved it; rather than fix a health problem, I now want to work to prevent the health problem in the first place by learning the root cause of the issues. Only then can effective preventive measures, such as better education models, improved regulations, etc., be made.

What was one of the biggest lessons you learned while at WCAHS?

How important it is to establish trust with the farmer and farmworkers when asking them to participate in a study. Establishing personal connections is crucial. The farmworkers were incredibly thankful that we were concerned about their welfare, and this increased their willingness to participate and learn about the signs of heat illness.

What inspires you about your work?

Definitely giving back to my community and helping them learn how to make positive, healthy changes. [Note: Jose comes from a Central Valley farmworker family and picked in the orchards as a teen. Read about Jose’s early life in the Summer 2011 WCAHS newsletter.]

What will you do at your new job?

I will be managing a wellness program for farmworkers. My new job will still be linked to UC Davis.  My new employer, Reiter Affiliated Companies, is hosting a study to test a comprehensive approach to improve cardiovascular health among Latino farmworkers. I will coordinate a team of health educators and research assistants, as well as maintain communication with the UC Davis based research team.

Leaving WCAHS is hard, both professionally and personally, because it is such a great place to work, but I will use the skills/knowledge I learned to continue striving to improve the quality of life of farmworkers.


Alifia Merchant: Determining Pesticide Exposure with Antibodies and 96 Tiny Wells

Alifia croppedBy Alifia Merchant

Agriculture and landscape workers apply pesticides as part of their work. Pesticides benefit us by protecting plants from harmful insects, but they can be poisonous if used carelessly.

Workers need to know how to safely use pesticides, such as by wearing gloves and long pants and washing their hands immediately afterwards. In California, many agriculture and landscape workers have a limited understanding of English and may not be able to read the instructions on how to apply pesticides safely. On the other hand, they may not have formal training through their employment, especially if their business is freelance. Even with trained workers, mistakes can be made.

My goal as a graduate student in the Agricultural and Environmental Chemistry Graduate Group at UC Davis is to help better protect agriculture and landscape workers from harmful pesticide exposure. I am working with Drs. Debbie Bennett and Bruce Hammock, Western Center for Agricultural Health and Safety (WCAHS) investigators, to develop quick and easy methods to determine if a worker has been exposed to pesticides.

Alifia blog photo copyI will interview agriculture and landscape workers to gain information about their jobs and possible pesticide exposure. Then, I will collect urine samples on days that they have sprayed or otherwise been exposed to pesticides.

Why am I collecting urine? When chemicals enter the body they can be metabolized, meaning that their chemical structure changes. After metabolism, the chemical can leave the body through urine. Different chemicals remain in the body for varying amounts of time, but the pesticides that I am studying are present in urine within several hours after exposure.

I will determine pesticide exposure using a method called enzyme-linked immunosorbent assay or ELISA for short. Each ELISA test involves a plate with 96 tiny wells with specific antibodies added to the wells. Each antibody detects a specific pesticide.

Urine will be added to the wells. If a well contains urine with pesticiELISAde metabolites, the well turns light yellow or clear. If the urine does not contain pesticide metabolites, the well turns a bright yellow color. Thus, the color of the well allows us to know if a person has been exposed to a pesticide and to what degree.

In the future, we see using the ELISA to quickly know if someone has been unsafely exposed to a pesticide and needs medical help. It could also be used to train workers; if the ELISA shows that a worker was unsafely exposed to pesticides after applying them, the worker would be informed about their results and receive recommendations about how to better protect themselves while doing their job.

For information on how to safely use pesticides at work and home, check out The Pesticide Safety Project website and videos in both English and Spanish, produced by WCAHS in collaboration with the California Poison Control System, and the California Department of Pesticide Regulation.


From Scorpions to Asthma: An interview with Alex Castañeda, WCAHS Seed Grant Award Winner

DSCN0277Alex Castañeda is a 4th year UC Davis graduate student. He was awarded a 2013-2014 WCAHS Seed Grant to help him study air pollution and asthma. Below, he talks about what led him to love science and work to improve agricultural health and safety.

Favorite high school subject: “Biology. My high school biology teacher was passionate about making students learn the material, not just memorize it.”

Family: “My parents are originally from Mexico. They encouraged me to go to college and are proud of me. They both were well educated in Mexico – my dad as an electrical technician and my mom as a nurse. While my mom became a full time homemaker with 3 kids in the U.S., she shared her love of science with me and the importance of helping people.”

Scorpions: “After getting a bachelor’s degree at UC Irvine, I went to CSU Bakersfield for a master’s degree. My project was to understand how scorpions are affected by their environment and human activity. Things like building roads and homes can isolate scorpions from each other and their populations can disappear. Depending on your view, this could be good or bad!”

Air Pollution and Asthma: “While working on the scorpions project, I learned about molecular biology and how the environment can really affect us. I decided to use the same scientific techniques to study lung disease at UC Davis. The WCAHS Seed Grant has helped me study how air pollution, especially the tiny particulate matter in the air, causes asthma.”

“Asthma is a major health problem in many agricultural areas of California, especially near Fresno and Bakersfield. We want to understand why this happening and if there are certain parts of air pollution that are worse than others. To do this, we collaborate with Dr. Keith Bein, an air quality researcher. He uses sophisticated equipment to capture air samples and separate out the different components for testing. Many of the different components are pollutants from regular activities, like driving and home cooking, and some agricultural practices, like pesticide application and plowing.”

“Our goal is to better protect people, especially those working in dusty agricultural environments, by understanding exactly which components pose the greatest risk to health. We have found that mice exposed to certain types of particulate matter are more likely to get asthma when they are exposed to something allergic.”

Advice to young students: “Volunteer. Doing activities through my church (soup kitchen) and high school student council (organizing events) opened my eyes to what I liked best – helping people. It feels great to know that what I am doing in the lab could be used to improve the health of people.”

Future plans: “I will graduate next year and plan to do an academic post-doc in a lab looking at lung disease. Staying in California would be great, but I’m open to other possibilities.”

WCAHS Seed Grants support graduate student education and training, assist in connecting students to agricultural health and safety careers, and are open to student researchers in the WCAHS four-state region: AZ, CA, HI, and NV.

For more information, contact WCAHS Manager, Cindy Valencia,