As attitudes toward marijuana become more lenient and states authorize its use for medicinal — or even recreational — purposes, a long simmering debate over the efficacy of workplace drug testing has found a new flash point.

Marijuana accounts for more failed workplace drug tests than any other substance, and the new laws have the potential of decreasing or eliminating employer testing for it.

Defenders of drug testing maintain that employees who use drugs, including marijuana, have been found to miss more work, cause more accidents, change jobs more frequently and ultimately cost employers more money.

Many of those defenders happen to be part of the drug test industry, comprising large diagnostic laboratories and smaller third-party companies, which has mobilized to oppose the wave of legislation and litigation that it expects to rise from the conflict between workplace policies and changes in laws. [Read more at the Pittsburgh Post-Gazette]