Exemptions to hours of service regulations for oil-field workers are killing workers, according to a story on the front page of Tuesday's New York Times, and it's a situation that could only get worse with the boom in oil and gas well drilling using hydraulic fracturing, or fracking.

In "Deadliest Danger Isn't at the Rig but on the Road," the paper takes a look at how highway crashes are the most dangerous part of working as a trucker in the oil or natural gas drilling business.

"Over the past decade, more than 300 oil and gas workers ... were killed in highway crashes, the largest cause of fatalities in the industry. Many of these deaths were due in part to oil field exemptions from highway safety rules that allow truckers to work longer hours than drivers in most other industries, according to safety and health experts."

Unlike the hours of service rules for most truckers, the rules allow oil field truckers to log waiting time at a natural gas or oil well site as "off duty."

Oil-field truckers tell the paper that the oil-field exemption is routinely used to pressure them into driving after shifts that are 20 hours or longer.

The article has pages and pages of documents relating to the story, including the National Transportation Safety Board's comments about being "strongly opposed" to the oil-field exemption and the industry's defense of the exemptions, many of them drawn from comments filed with the federal government on the last hours-of-service rule proposal.

In those documents, one driver described waiting 36 hours to unload without a place to lie down and sleep. "No driver should be expected to wait more than 14 hours without an opportunity to lie down and rest," he wrote. "Not sitting up in a day cab for 36 hours, and then expected to operate their equipment. It's unsafe." Oilfield crews, he said, only work 12 hours, then go home or to a motel.

The problem is likely to get worse, the paper notes. "According to federal officials, more than 200,000 new oil and gas wells will be drilled nationwide over the next decade. And the drilling technique used at more than 90% of these wells, known as hydraulic fracturing, or fracking, leads to far more trucks on the road - roughly 500 to 1,500 truck trips per well - than traditional drilling, partly because fracking requires millions of gallons of water per well."

Nearly a third of the 648 deaths of oil field workers from 2003 through 2008 were in highway crashes, the Times reports. By contrast, highway crashes caused roughly a fifth of workplace fatalities across all industries in 2010.

A spokesperson for the Federal Motor Carrier Safety Administration told the paper that the oil field exemptions did not apply to all trucks in the oil and gas industry, but many safety advocates say oil and gas companies routinely apply the exemptions to vehicles that aren't supposed to be covered, such as large tankers that haul waste and water. And enforcing the rules is difficult, said the Commercial Vehicle Safety Alliance.

It's a fascinating read and an interesting angle on the whole hours of service and fatigue question.