When Shelton trucker Randy Mack climbs behind the wheel, he's pulling more than just a load of cargo. He's also carrying the huge weight of responsibility that comes with driving his 50-ton big rig.

“It ain't like driving your ordinary car or pickup down the road,” he said. “You need 10 times the stopping distance to get one of these stopped.”

With the stakes so high, Garland Massingham had no place behind the wheel of a semi. The 41-year-old Centralia man is a convicted methamphetamine cook who violated his probation three times using the drug. He was also a trucker on a collision course with the lives of two women.

“That was an event waiting to happen and it happened at that time Dan and Tony were on that same curve," said Eileen Llona.

Llona's husband, Daniel Johnson, was a geophysicist. Kathleen Ellsbury's husband Tony Qamar was the official state seismologist.

Both men were returning from a project on the Olympic Peninsula when a log truck dumped its load on their car, killing the respected scientists - and beloved husbands - instantly.

"It's like the breath has been taken out of your body... it's like your heart has been ripped out of your body,” said Llona.

"The first days I was under the impression that this was a true accident," said Ellsbury.

But in the weeks that followed, family learned that the log truck was speeding, was nearly four tons overweight, and that driver Garland Massingham tested positive for meth.

Worse yet, he was still on the road, driving a log truck.

“I was taken aback when I heard that. I couldn't believe it," said Ellsbury.

By law, truckers undergo random drug testing, and a positive hit can mean a suspension of their commercial driver’s license. Drug tests are also required after serious accidents.

But we've uncovered a string of flaws in regulations that kept Massingham on the road and destined for more mishaps.

State and federal laws allow a trucker up to 32 hours to report for a post-accident drug test. After this crash, Massingham gave a urine sample 27 hours later.

Christine Clark of Premium Drug Screening, Inc. provides tests for several trucking companies. She scoffs at the 32-hour rule.

'It's too long. Too many drugs flush out too fast," she said. “I feel they should be tested at least within the first eight hours."

The KING 5 Investigators spoke to several drug experts who agree that in 32 hours, drugs can flush from the human body, naturally or through excessive water intake and exercise. It’s a common trick to beat a urine test.

“The drug concentration in that particular urine specimen is going to be to some extent washed out," said Dr. Andrew Saxon, VA Puget Sound.

Massingham's urine test came back negative, but he wasn't in the clear.

We reviewed state patrol logs that show within six hours of the crash, Massingham agreed to trooper requests for a voluntary blood test, which later came back positive for methamphetamine.

But remarkably, Massingham was still free to drive. The Department of Licensing ruled that federal laws do not allow the agency to revoke a commercial drivers license based on a blood test, only the urine test which Massingham took much later and passed.

“What we're talking about is a test that was taken by State Patrol. That's not part of the policies and processes related to a DOT drug test,” said Brad Benfield of the Department of Licensing.

But the DOT itself strongly disagrees. The US Department of Transportation says there's nothing in federal law blocking the use of Massingham's blood test.

A DOT spokesman told the KING 5 Investigators the state could have yanked his license right after the fatal crash.

Instead, Massingham was free to get into more trouble on the road.

Through a search of public documents, we uncovered records showing that Massingham was again ticketed for overloading his log truck.

“Why was he not pulled off the road at that time? I didn't know this until now," said Llona.

A few months later there was another spill, without injuries, outside a log yard in Shelton.

Massingham was still driving for J.B. Leonard, a trucking company with a history of safety violations.

This time, Massingham tested positive for amphetamine.

“It's horrifying. This is Massingham and the Leonards spitting on our husband's graves," said Ellsbury.

Fourteen months after the fatal crash, a judge sent Massingham to jail to keep him off the road while awaiting trial on the vehicular homicide charges to which he eventually pled guilty.

With officially only one positive drug test on his driving record, he will not face the licensing department's ultimate ban - a lifetime driving suspension. He could drive a truck again in the State of Washington.