Greenhouses are becoming more popular, but there is little research on how to protect workers

From opposite ends of the world, the uncomfortable conditions that Shamim Ahamed and Purvi Tiwari experienced while pursuing doctorates separately. research inside greenhouses inspired them to study heat in internal structures.

Tiwari, a researcher at Indira Gandhi Agricultural University in India, realized that the heat-amplifying effect of greenhouses is a major concern that should be studied because she herself experienced the leg cramps, nausea and dizziness that her farmers later described. Summer outdoor temperatures can reach 50 degrees Celsius (120 degrees Fahrenheit) in parts of India, where greenhouse workers “feel suffocated inside.” She added that over the past five years, greenhouses have become a trend as available land dwindles amid development.

“Workplaces shouldn’t harm humans,” she said. “If that area of ​​work is harming that person, that means it’s not good to work in. This should be changed.”

In the United States, the latest agricultural census shows that the number of greenhouse and nursery workers in the US has increased by 16,000 in recent years. But there are no federal rules on heating, even as greenhouses become more popular and the number of workers in them increases. There is also little research into the experiences of workers and their wider working conditions, nor into how to protect people working in their often hot and humid environments. But academics around the world, like Tiwari and Ahamed, are trying to fill gaps in knowledge about the unique conditions that farm workers in greenhouses are exposed to.

Bharat Jayram Venkat, associate professor and founding director of UCLA’s Heat Lab, said “there’s a lot of research on farmworkers…but not looking specifically at greenhouses.” not on human health.

“At first glance, it makes sense – that’s what greenhouses are for. But of course you need human workers in these greenhouses to make them work,” he said, “so you have to think about human health.”

More heat, more greenhouse workers

Last year was the hottest on record and U.S. cities have repeatedly experienced triple-digit temperatures. According to the United States Department of Agriculture, the number of farms and square feet under glass and the value of greenhouse and nursery sales have increased since 2017. Additionally, use of the H-2A program for agricultural workers has essentially doubled over the course of 2017. of the year. period 2010-2019, with implications for workers’ ability to complain about extreme heat conditions.

Venkat predicts that more research will emerge as indoor, climate-controlled growing environments will likely become more popular as weather conditions become less predictable and more extreme. Laws like California’s Newly Approved Indoor Heating Rules and the increase in the number of greenhouse workers will also increase interest in studying them, he said.

Jennifer Vanos, an associate professor at Arizona State University, has researched the limits of survival and physical work capacity in extreme heat. Using research led by a former Loughborough University fellow – who assessed how the body functions under different temperatures, wind speeds, humidity and radiation – Vanos and colleagues studied the productivity of agricultural workers on a warming planet.

One of their conclusions was that the hotter it gets, the less productive workers may be, which has economic implications. In the context of agriculture, this could mean fewer crops and the need for more workers.

Ultimately, their results concluded that “for people to work safely, they have to lower their heart rate, which means lowering their training output to be able to perform the same tasks in a warmer environment,” Vanos said.

Signs of heat stress include intense sweating, cramps and rapid heartbeat. Exposure to extreme temperatures can increase the risk of injury due to dizziness, weakness or fainting. And heatstroke, the most serious heat-related illness, can occur when the body stops sweating and the temperature rises.

When heat combines with humidity, it is more difficult for sweat to evaporate to cool the body, creating a potentially more dangerous situation.

“When the air is already really saturated with water vapor… the ability to evaporate sweat decreases significantly,” said Venkat. “This means the risk of heat-related illness or even death will be much higher.”

Filling research gaps

Researchers Tiwari and Ahamed have now published articles on greenhouse environments. Ahamed, now an assistant professor in the Department of Biological and Agricultural Engineering at UC Davis, has studied the risks of heat exposure in high-tech greenhouses, comparing the effects on workers when tools like shade “skins” are deployed in greenhouses to maintain temperatures. lower temperatures. . Tiwari spoke to workers in India who experienced nausea, drowsiness and dehydration, and she and her team found that greenhouse workers who worked in the middle of the day had an average working heart rate 20% higher than workers in open fields.

Ahamed said Tiwari’s research is relatively rare. Many of the studies that exist are carried out in countries outside the USA. And even when studies are based in the US, it can be difficult to obtain an adequate sample size for greenhouse workers in particular.

For example, researchers at UC Merced found higher rates of premature births, low birth weight and birth defects in pregnant agricultural workers at all levels – including field and daycare workers. A study in Iran found similar effects on greenhouse workers there, but the UC Merced team said there weren’t enough pregnant agricultural workers in the countryside to confidently analyze that result alone.

Gaps in the literature, Ahamed said, led to “a huge gap in how these things could be regulated or standardized.” He thinks there needs to be building codes based on exposure to UV rays, heat and humidity, as well as safety procedures for indoor workers.

But with such a wide range of greenhouse technology being used – from megafarms on many acres to microclimates created with “high tunnel” or “hoop house” configurations involving plastic arched over small sections of a field – the patchwork of possible options remains a problem. issue regarding the implementation of standards.

However, he thinks it would be possible to implement different protocols depending on the type of greenhouse available.

“To do this, they need to investigate, find some recommendations,” said Ahamed.

___

The Associated Press’ climate and environmental coverage receives financial support from several private foundations. AP is solely responsible for all content. Find APs standards for working with philanthropies, a list of supporters and areas of coverage funded in AP.org.