“All indications are that it’s a growing problem, and we’re seeing it more publicly available,” said NTSB Chairman Christopher Hart in an interview after a hearing in Washington. “This is a fresh and scary and growing problem. We need to get some controls around these synthetic drugs. It’s shocking to me that if I’m a truck driver, I can buy this in a truck stop.”

Cannabinoids targeted

The safety board recommended new standards and testing to determine the extent of synthetic drug use, particularly cannabinoids, among commercial truck drivers, and it urged the industry to take new steps to detect such abuses.

Four students from Northern Central Texas College died on on Sept. 26, 2014, near Davis, Oklahoma, when their bus was hit by a truck driven by Russell Staley, who had a history of using synthetic drugs. He drove 1,100 feet across a grassy median, never slowing down or steering before striking the bus. He then drove another 300 feet into nearby woods.

Investigators said he was unaware that he had even hit the bus as his truck continued on into the trees.

After the crash, investigators found a silver pipe with burnt residue of 5-fluoro-AMB, a synthetic cannabinoid, but later testing could not confirm or rule out its presence in Staley’s blood, according to the NTSB. Investigators ruled out other factors, including fatigue, saying Staley’s failure to respond to driving off the roadway for 11 seconds was likely caused by synthetic drugs.

Seizure-like symptoms

Staley needed help for his dependency on synthetic cannabinoids, also known as K2, and had seizure-like symptoms, his wife told his doctor 13 months before the crash, according to records released by the NTSB. Notes from Staley’s licensed professional counselor in August 2013 also showed he said he “had been using designer drugs at work” and needed help with stress, anger, low self-esteem, guilt and depression.

Staley was charged with four counts of manslaughter and faces trial next year.

The injuries to the 15 people in the bus were worse because they weren’t wearing seat belts, and their vehicle wasn’t strong enough to withstand the crash, the board said. The softball coach who was driving also didn’t require the students wear seat belts, and the college had no policy in place to ensure that he do so, the NTSB added.

Related: 5 solutions for Workers' Comp challenges in the trucking industry

After the crash, investigators sent samples of Staley’s blood to three labs, including two that could test for the presence of synthetic cannabinoids, but the results were inconclusive. They also could only find a one in 38 chance that the DNA on the pipe found in Staley’s truck was his.

Staley had worked for Quickway Transportation Inc. for only a few months when the accident occurred. He was 47 miles north of the Oklahoma-Texas line at 9:05 p.m. that night when the road curved slightly to the right, and his rig did not.

Four killed

The accident killed Jaiden Pelton, 19, of Telephone, Texas; Brooke Deckard, 20, of Blue Ridge, Texas; Meagan Richardson, 19, of Wylie, Texas; and Katelynn Woodlee, 18, of Dodd City, Texas. The team was returning home from a scrimmage at Southern Nazarene University in Oklahoma.

The NTSB released 2,000 pages of documents late Monday, including a transcript of a whistle-blower call to the board from a supervisor who worked for Staley’s previous employer. Staley had been missing work, showing up late and not performing well, the supervisor told a board investigator.

Staley told the supervisor he was smoking synthetic marijuana, which he referred to as spice. Staley told him that he had passed out in a park and didn’t know how long he had been there. When the supervisor told his boss about Staley’s problem, “it fell on deaf ears,” and the company neither took him off the road nor got him assistance, according to the report.

“I told him, I said this guy’s going to kill somebody someday, you watch,” the supervisor said he told his boss. “And I’ll be damned, it happened.”

--With assistance from Margaret Newkirk.

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