VERNAL — When staffers with Intermountain Toxicology showed up at oil and gas rigs in the Uinta Basin a year ago, entire crews of roughnecks climbed into their trucks and drove away from their lucrative jobs — some paying more than $22 an hour — rather than submit to drug testing.

"There was this mentality that, 'We can leave this company because we can go two blocks down the road, and they'll hire us because they don't have a (drug-free workplace) policy,' " Intermountain Toxicology owner Jonna May said recently, describing the scene as "dirt and cars just scurrying away — dust clouds."

May said the random tests frequently turned up positive results for cocaine and marijuana, but more commonly they found methamphetamine, which she called "the most dominating drug out there." However, an emphasis by oil and gas companies to combat drug use among employees has led to more stringent substance-abuse policies and a somewhat cleaner working environment.

"Now you'll test at least half the crew, and the other half will leave," said May, whose firm works with more than 100 companies in the energy-exploration industry and travels to remote drilling sites to test rig crews.

Some employers have instituted a "last-chance policy," allowing workers to stay on after a positive drug test, if they admit they have a problem and seek treatment. May said the policy is a toned-down approach from the zero-tolerance stance companies were operating under until recently. The shift happened, she said, because of the need to keep enough people working in the oil-field.

Figures from the Utah Division of Oil, Gas and Mining show that by last December, Duchesne and Uintah counties accounted for 85 percent of the 887 new oil and gas wells drilled in Utah in 2005. This year, as of Friday, there were already 439 more new oil and gas wells being drilled in the state, with 92 percent located in the Uinta Basin.

Police say the population growth associated with the energy boom has spawned an increase in arrests for drug charges and other related crimes in eastern Utah. Police in Vernal, the hub of operations for many of the larger oil and gas companies, handled 130 drug cases in 2005, which doesn't include drug arrests by the Uinta Basin Narcotics Strike Force or Uintah County Sheriff's Department. Of those 130 cases handled by Vernal, 39 were for the possession, distribution or manufacture of meth.