(11-07) 04:00 PST Sacramento -- A divided California Supreme Court grappled Tuesday with the application of the state's medical marijuana law in the workplace, debating whether an employee who uses pot to cope with pain or illness can be fired for violating federal drug laws.

The case of Gary Ross, a 45-year-old computer technician fired by a small Sacramento firm for failing a drug test, is the latest in a series of federal-state conflicts since California voters approved Proposition 215 in 1996, legalizing the medical use of marijuana if a doctor recommends it. At least 11 states have since adopted similar laws.

The U.S. Supreme Court has upheld the federal government's authority to shut state-approved medical marijuana dispensaries and prosecute patients and their suppliers for violating federal laws that ban marijuana possession, cultivation and distribution. But the application of Prop. 215 to issues of hiring and firing depends mostly on the meaning of California law - the 1996 initiative, a follow-up legislative measure and a disability discrimination law - on which the state's top court is the final authority.

The state's voters intended to allow medical marijuana users "to fully participate in life regardless of any potential disability," Stewart Katz, a lawyer for Ross, told the court during Tuesday's hourlong hearing in Sacramento. That includes having a job, he said.

But several justices noted that although Prop. 215 protected medical marijuana users and their caregivers from state criminal prosecution, it never mentioned the workplace.

If the initiative was intended to give medical marijuana patients the same rights as other Californians to get and keep jobs, "don't you think it would be brought to the attention of the electorate?" asked Justice Kathryn Mickle Werdegar.

Another attorney for Ross, Joseph Elford of the medical marijuana advocacy group Americans for Safe Access, replied that the law, like other initiatives, should be interpreted liberally to carry out the voters' intent and that it was often the court's job "to fill in the gaps of the statute."

"But not to rewrite it," said Chief Justice Ronald George.

Ross, according to his lawsuit, injured his back while in the Air Force in 1983 and suffers painful spasms for which he got no relief until 1999, when his doctor recommended marijuana.

He was hired as a computer administrator by the Sacramento firm, RagingWire Communications, in September 2001 and was fired 11 days later for testing positive for marijuana.

Ross said he took a copy of his doctor's note to the drug-testing clinic, never used the drug at work or was impaired by its effects on the job, and performed his duties competently. His suit accused RagingWire of violating a state law that prohibits discrimination against disabled employees and requires employers to make reasonable accommodations.

The state Supreme Court, which is scheduled to rule within 90 days, granted review of the case after lower courts ruled that the company had the right to fire Ross for using a drug that was banned by federal law.

Numerous medical and disability groups have filed written arguments on Ross' side, while business organizations have come to RagingWire's defense, noting among other things that companies that hire drug users might forfeit federal contracts.

An employer who hires a medical marijuana user is "arguably being complicit in an activity that's illegal under federal law," RagingWire's lawyer, Robert Pattison, told the court. He said the state law that requires employers to offer reasonable accommodations to the disabled shouldn't be interpreted to require accommodation of illegal drugs.

But Justice Joyce Kennard said that under Prop. 215, "it is not a crime when someone engages in the use of marijuana under supervision of a physician." Keeping Ross on the job would have promoted the goals of the disability law without exposing the company to prosecution, she said.