Smoking marijuana in your off-time doesn’t necessarily make you responsible for a workplace mishap that may follow, the Tennessee Supreme Court has ruled in the case of a Knoxville man whose hand was crushed on the job.

The state’s high court ruled that Billy McIntosh, whose hand got caught in a power roller machine that bends sheet metal while working for Interstate Mechanical Contractors Inc. in Knoxville in 2004, was not to blame for the accident despite his admitted marijuana use off the job, the Associated Press reports.

McIntosh, who was 51 at the time of the injury, testified that while showing a new employee how to use the machine, he reached over it from behind to set a piece of metal when the new employee engaged the rollers, which then grabbed McIntosh's hand and pulled it into the rollers.

The stunned co-worker was unable to help, so McIntosh was forced to disengage the machine himself and then reverse the rollers to release his hand, the ruling says.

Doctors were forced to partially amputate his middle and index fingers, and McIntosh still cannot extend his ring and small fingers.

At the hospital, McIntosh tested positive for marijuana. He admitted he smoked it in the week leading up to and on the night before his injury but denied smoking it or being impaired the day of the accident.

Interstate Mechanical filed a petition in Chancery Court for Knox County alleging McIntosh violated its drug-free workplace policy and should be denied workers’ compensation, arguing that the drug use impaired his reaction time and was the cause of the injury.

The state law establishing the drug-free workplace program presumes that any injuries to an employee found to have been using drugs or alcohol were caused by the drug use. But the court noted that the law also allows employees to enter evidence to rebut that presumption.

A drug screen on McIntosh's blood showed THC — the chief mood-altering chemical in marijuana which can be detected in the body up to 30 days after smoking marijuana.

A medical toxicologist testified in a deposition "that the level of THC in McIntosh's system at the time of the injury would have impaired his reaction time," the ruling states.

The co-worker and the shop foreman both testified that McIntosh didn't appear to be impaired by marijuana use before the accident.

McIntosh, who had worked at Interstate for five years, contended the injury was caused by the actions of an inexperienced employee. The trial court ruled in favor of McIntosh, and the state Supreme Court upheld that in a ruling released last week.

"In this case, the undisputed evidence ... was that there would be no time to react if a person had a hand next to a roller when it was engaged," Justice William M. Barker wrote in the Supreme Court ruling.