The temperature has soared to 107 degrees at the Hanford Nuclear Reservation this summer.
In the tank farms, workers pull on three pairs of gloves, cover their faces with respirator masks and carry tanks of oxygen on their backs.
They don impermeable suits that keep radioactive contamination and hazardous chemicals from reaching their skin, but also trap in heat and moisture.
Yet, tank farm workers are going on their third summer with no cases of heat exhaustion or heatstroke.
Washington River Protection Solutions, the Hanford tank farm contractor, is using a new program that monitors workers to stop heat-related disorders from developing before a worker is sickened.
Historically, the tank farms have measured air temperature, humidity, wind movement and heat from the sun – called the wet bulb globe temperature – to determine when weather conditions might put workers at risk of overheating.
The method was developed for the military and works well for soldiers, who are uniformly young and physically fit, said Edward Sinclair, the industrial hygienist who leads the tank farms heat stress program.
But at the Hanford tank farms, workers range in age from 18 to 68 and have different levels of physical fitness, and some are on medications for chronic health issues that may affect their ability to handle the heat.
The old method left workers watching out for each other and reporting possible symptoms, as a backup to weather monitoring. If workers thought they or a coworker might have heat-related symptoms, they were pulled off the project, removed their layers of protective clothing and had their heart pulse rate measured.
Work was sometimes stopped as a precaution, because it was difficult to predict if workers could physically handle the weather.
But workers still were developing heat-related disorders. More heat was coming into their bodies than their bodies could release, causing heat exhaustion, which can lead to life-threatening heatstroke.
The new program takes a personalized, worker-by-worker approach.
“(It) removes employees from harmful heat-related tasks before they develop heat stress symptoms,” said Mark Lindholm, president of Washington River Protection Solutions.
Because the heart has to work harder in hot temperatures, heart rate monitors are used to measure the level of an individual’s heat strain. Body temperature checks can provide additional information.
For the most taxing work, such as digging trenches or tearing down or putting up scaffolds, workers wear a heart rate monitor on a chest strap.
Data is transferred in real time to the electronic tables of industrial hygiene technicians, who watch data for no more than seven or eight workers at a time.
“They watch every second,” Sinclair said.
Workers are pulled off a job to cool down if their heart rate indicates their body might begin to struggle with the heat.
For work that is considered light to moderate, a finger monitor can be clipped on over the layers of work gloves for a check every 15 minutes.
The new program also uses a highly accurate ear thermometer. Workers with a naturally high resting heart rate may need checks of their core body temperature every 15 to 30 minutes because their heart rate cannot be used as an indicator of heat strain.
Not only have workers stayed healthier, but more hours are being worked, according to Washington River Protection Solutions.
The monitoring program received the 2017 Campbell Innovation Challenge award, an award of the Campbell Institute at the National Safety Council for programs that address environmental, health and safety issues with creative thinking and significant impact.
The monitoring methods have been adopted at other DOE sites, including in New Mexico, Tennessee and South Carolina, according to Washington River Protection Solutions.
Sinclair says companies with workers laboring in hot climates also are taking notice. He’s fielded inquiries from Kuwait, Australia and oil and gas companies in Texas.
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