Sensors can measure sweat levels and predict overheating.

(AP) — On a hot summer day in Oak Ridge, Tennessee, dozens of men removed pipes, asbestos and hazardous waste as they worked to decontaminate a nuclear facility and prepare it for demolition.

Dressed head-to-toe in hazmat suits and equipped with respirators, the crew members working in a building without electricity had little visible respite from the heat. Instead, they wore wristbands that tracked their heart rate, movements and exertion levels to detect signs of heat stress.

Stephanie Miller, a health and safety manager for a U.S. government contractor that does cleanup work at Oak Ridge National Laboratory, watched a computer screen nearby. A color-coded system with tiny bubbles showing each worker’s physiological data alerted her if someone was in danger of overheating.

“Heat is one of the biggest hazards we face in this job, even though we deal with high radiation, hazardous chemicals and heavy metals,” Miller said.

As the world experiences rising temperatures, employers are exploring wearable technology to keep workers safe. New devices collect biometric data to estimate body temperature—a high temperature is a sign of heat exhaustion—and encourage workers to take breaks to cool down.

Originally developed for athletes, firefighters and military personnel, the devices are now being used at a time when the Atlantic Council estimates that heat-related loss of work productivity could cost the United States about $100 billion a year.

But there are concerns about how medical information collected about employees will be protected, with some labor groups worried that managers could use it to punish people for taking needed breaks.

“Anytime you put a device on a worker, there’s a lot of concern about tracking, privacy and how are you going to use this against me,” said Travis Parsons, director of occupational health and safety at the Laborers’ Health and Safety Fund of North America. “There are a lot of exciting things, but there are no safeguards around them.”

HEAT SENSITIVE

At the Tennessee cleanup site, workers wearing heat stress monitors made by Atlanta-based SlateSafety are employed by United Cleanup Oak Ridge. The company is a contractor for the U.S. Department of Energy, which has regulations to prevent overheating in the workplace.

Yet most U.S. workers have no protection from extreme heat because there are no federal regulations requiring it, and many exposed workers don’t speak up or seek medical attention. In July, the Biden administration proposed a rule aimed at protecting 36 million workers from heat-related illnesses.

According to the Environmental Protection Agency, 986 workers have died from heat exposure in the U.S. from 1992 to 2022. Experts suspect the number is higher because a coroner may not list heat as a cause of death if a hot roofer falls to his death.

Setting safety standards for workplaces can be difficult because people react to heat differently. That’s where wearables makers hope to step in.

HOW WEARABLE THERMAL TECHNOLOGY WORKS

Employers monitored workers for heat stress by taking their temperatures with thermometers, sometimes rectally. More recently, firefighters and military personnel have been known to swallow thermometer capsules.

“It just wouldn’t work in our work environment,” said Rob Somers, global director of environment, health and safety at consumer goods company Perrigo.

Instead, more than 100 workers at infant formula plants were fitted with SlateSafety wristbands. The devices estimate the wearer’s body temperature, with a reading of 101.3 degrees setting off an alarm.

Another SlateSafety customer is Cardinal Glass in Wisconsin, where four stonemasons operate a kiln that reaches temperatures of 3,000 degrees Fahrenheit.

“They’re right up against the wall. So it’s them and the fire,” said Jeff Bechel, the company’s safety manager.

Cardinal Glass paid $5,000 for five wristbands, software and air-monitoring equipment. Bechel believes the investment is paying off; two employee emergency room visits due to heat cost the company $15,000.

Another wearable device, made by Massachusetts-based Epicore Biosystems, analyzes sweat to determine whether workers are at risk of dehydration and overheating.

“Just a few years ago, you were just wiping (sweat) off with a towel,” said CEO Rooz Ghaffari. “It turns out we have all this information that we were missing.”

Studies have shown that some devices are effective at predicting core body temperature in controlled environments, but their accuracy remains unproven in dynamic workplaces, according to experts. A 2022 review of studies found that factors such as age, gender and ambient humidity make it difficult for this technology to reliably measure core body temperature.

United Cleanup Oak Ridge workers dressed in protective gear can get sweaty even before demolition begins. Supervisors see dozens of sensor alerts every day.

Worker Xavier Allison, 33, was removing heavy ductwork during a recent heatwave when his machine vibrated. Because he was working with radioactive materials and asbestos, he couldn’t go outside to rest without undergoing a decontamination process, so he spent about 15 minutes in a nearby room that was just as hot.

“Just sit by yourself and do what you can to cool down,” Allison said.

The wristband notifies employees when they have cooled down enough to return to work.

“Since implementing this method, we have seen a significant decrease in the number of people seeking medical attention,” Miller said.

COLLECTION OF PERSONAL DATA

United Cleanup Oak Ridge uses sensor data and an annual physical to determine work assignments, Miller said. After noticing patterns, the company sent several employees to their personal doctors, who discovered heart problems the employees didn’t know they had, she said.

At Perrigo, managers analyze the data to find people with multiple alerts and talk to them to see if there’s “a reason they can’t work in this environment,” Somers said. The information is organized by identification numbers, not names, when it goes into the company’s software system, he said.

Companies that collect medical data for years have raised concerns about privacy and whether bosses would use the information to kick an employee off a health plan or fire them, said Adam Schwartz, director of privacy litigation at the Electronic Frontier Foundation.

“Honestly, this device can be a pain because you can raise your hand and say, ‘I need a break,’ and your boss can say, ‘No, your heart rate is not elevated, go back to work,’” Schwartz said.

To minimize such risks, employers should allow employees to turn monitoring devices on or off, process only necessary data and delete the information within 24 hours, he said.

Wearing such devices could also expose workers to unwanted advertising, said Ikusei Misaka, a professor at Musashino University in Tokyo.

PARTIAL SOLUTION

The National Institute for Occupational Safety and Health advises employers to put in place a plan to help workers adapt to hot conditions and train them to recognize the symptoms of heat-related illnesses and provide first aid. Wearable devices can be part of an effort to reduce heat stress, but more work needs to be done to determine their accuracy, said Doug Trout, the agency’s medical officer.

This technology must also be coupled with access to breaks, shade and cool water, as many workers, especially in agriculture, fear retaliation for taking breaks to cool off or hydrate.

“If they don’t have water to drink and time to do it, it doesn’t mean much,” said Juanita Constible, a senior staff attorney at the National Resources Defense Council. “It’s just something extra they have to carry when they’re in hot fields.”