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One of the oldest known workplace dangers is silica dust. Silica is basically sand and breathing in tiny particles can cause serious lung diseases like silicosis and cancer. Traditionally, silica exposure has been associated with jobs like mining, manufacturing and construction. But as NPR's Nell Greenfieldboyce reports, safety officials recently realized that this old danger could be a problem for workers in a newly booming industry, fracking.
NELL GREENFIELDBOYCE, BYLINE: New drilling sites for oil and gas are popping up all over, and the hydraulic fracturing part of the job happens quickly. Once a well is up and running, contractors move on to the next one. That's made it hard for workplace safety inspectors to see fracking in action. But not too long ago, a researcher named Eric Esswein got to do just that.
He's with the National Institute for Occupational Safety and Health, and this agency wanted to study the potential chemical hazards for oil and gas workers.
ERIC ESSWEIN: We really came into this with pretty much a tabula rasa, you know, kind of an open slate where we weren't really sure all the things that we could potentially look at.
GREENFIELDBOYCE: He thought they'd probably assess workers' exposures to chemicals like drilling fluids. But when he started visiting fracking sites, he saw big machines hauling around huge loads of sand. Sand is a critical part of fracking. After workers drill down into rock, they create fractures in that rock by pumping in a mixture of water, chemicals and sand. Lots and lots of it. The sand keeps the cracks propped open so that oil and gas is released.
ESSWEIN: When sand was handled, that is, when it was transported by machines on site or whenever these machines that move sand were refilled, dust, visible dust was created.
GREENFIELDBOYCE: Plumes of this dust surrounded machine operators and Esswein thought, this could be real hazard. Silica can cause chronic and even fatal lung diseases. That's why the government has long set limits on how much workers can inhale.
ESSWEIN: Knowing what I know about silica and respirable dust, that was the particular chemical that we chose to look at.
GREENFIELDBOYCE: He and his colleagues visited 11 fracking sites in five states: Arkansas, Colorado, North Dakota, Pennsylvania and Texas. At every site, the researchers found high levels of silica in the air. Seventy-nine percent of the collected samples exceeded the recommended exposure limit set by Esswein's agency. There were some controls in place.
ESSWEIN: At every site that we went to, workers wore respirators.
GREENFIELDBOYCE: But about a third of the air samples they collected had such high levels of silica, the type of respirators typically worn wouldn't offer enough protection. Now, these unexpected findings have come just as federal safety officials are trying to set stricter controls on silica for all industries. Some proposed new rules have been under review at the White House for more than two years.
Peg Seminario is with the AFL-CIO, a group of unions that's been pushing for stronger silica regulation. She says the situation with fracking is a wake-up call.
PEG SEMINARIO: Hopefully, it will give some impetus to the need for the silica regulation, that there is a whole other population at risk and those numbers are potentially growing.
GREENFIELDBOYCE: Government officials and the fracking industry say they're now working together to reduce worker exposures. They started with quick fixes like putting up warning signs and simply closing hatches on sand-moving machines. Some oil and gas companies are also testing new technologies. Tim Hicks is a safety expert with Encana. He says they've been trying out vacuum systems that are attached to sand-moving machines and suck up the dust.
Hicks says the results so far are encouraging, but his company is still testing to see how much of a reduction in airborne silica is reasonably achievable.
TIM HICKS: We'd like to envision a site, you know, we could handle sand and sequester it all, and perhaps someday not need to use respirators.
GREENFIELDBOYCE: Whether that's possible or how long that would take, he's not sure.
HICKS: But I can say that at the rate we're going, we're much more likely to hit that than we were prior to this issue being recognized.
GREENFIELDBOYCE: Asked why the industry didn't recognize this health risk earlier, Hicks said he'd only been working in this part of the oil and gas business for a few years and couldn't speculate, but that people seemed to think the dust was basically just dirt. Nell Greenfieldboyce, NPR News.