[##_1L|1223052704.jpg|width="130" height="90" alt=""|_##]When Gary Ross was ordered to take a drug test at his new job, the recently hired computer tech had no doubt the results would come back positive for marijuana. But along with his urine sample, Ross submitted a doctor's recommendation that he smoke pot to alleviate back pain _ a document he figured would save him from being fired.

It didn't: Ross was let go eight days into his tenure because his employer, Ragingwire Inc., said federal law makes marijuana illegal no matter the use.

On Tuesday, the California Supreme Court is due to hear Ross' case, the latest example of the intensifying clash between federal and local authorities over marijuana use.

Ross, 45, contends that Ragingwire discriminated against him because of a back injury and violated the state's fair-employment law by punishing him for legally smoking marijuana at home.

He says he and others using medical marijuana should receive the same workplace protection from discipline that employees with valid painkiller prescriptions do. California voters legalized medicinal marijuana in 1996.

Eleven other states, including Alaska, Colorado, Hawaii, Maine, Montana, Nevada, New Mexico, Oregon, Rhode Island, Vermont and Washington state have adopted similar laws and many are now grappling with the same sticky workplace issue of employee use of medicinal marijuana.

The nonprofit marijuana advocacy group Americans for Safe Access, which is representing Ross, estimates that 300,000 Americans use medical marijuana. The Oakland-based group said it has received hundreds of employee discrimination complaints in California since it first began tracking the issue in 2005.

"It's an extremely widespread problem," said Joe Elford, the group's chief lawyer.

Several national medical organizations and disability rights advocates have filed friend-of-the-court papers urging the Supreme Court to rule in Ross' favor.

Ross, who lives in Sacramento, said he permanently injured his back in 1983 while serving as a U.S. Air Force mechanic. He said it wasn't until 1999 that he found true pain relief with marijuana.

The American Medical Association advocates keeping marijuana classified as a tightly controlled and dangerous drug that should not be legalized until more research is conducted.

"I think I'm standing up for everybody else," Ross said. "My motivation is that I don't like to lose and that medical marijuana is effective."

So far, though, Ross has been losing.

Two lower courts have sided with Ragingwire's decision to fire Ross because federal law holds that marijuana is illegal in all guises and a 2005 U.S. Supreme Court decision declared that state medicinal marijuana laws don't protect users from criminal prosecution.

Ragingwire marketing chief Doug Adams declined to comment on the case.

Ragingwire, a small telecommunications company in Sacramento, has been joined in the Supreme Court by powerful corporate interests such as the Santa Clara Valley Transportation Authority and the Western Electrical Contractors Association Inc., who said companies could lose federal contracts and grants if they allowed employees to smoke pot.

The conservative nonprofit Pacific Legal Foundation said in a friend-of-the court filing that employers could also be liable for damage done by high workers.

"History abounds with cases of employers found liable," the Sacramento-based foundation wrote, "because their employees were driving vehicles, operating heavy equipment or otherwise performing tasks made more dangerous by their being under the influence of alcohol or drugs."