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A Walmart employee with sinus cancer and an inoperable brain tumor who was fired for using medical marijuana will not be rehired, even though the company says it is "sympathetic" to his condition.

Joseph Casias, 29, was fired in November from a Walmart store in Battle Creek, Mich., after marijuana was detected in a routine drug screening that he underwent after he sprained his knee at work.

Casias, who was the store's 2008 associate of the year, said he legally used marijuana to reduce pain associated with his disease and was never under the influence while at work.

"I gave them everything," Casias told Wzzm13.com. "110 percent every day. Anything they asked me to do, I did. More than they asked me to do. Twelve to 14 hours a day."

Casias, who has been collecting unemployment since his termination, reportedly received a notification this week that Wal-Mart was challenging his eligibility for benefits. But Wal-Mart officials will no longer object to Casias receiving those benefits, company spokesman Greg Rossiter told FoxNews.com.

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    "This is just an unfortunate situation all around," Rossiter said. "We're sympathetic to Mr. Casias' condition, but like other companies, we have to consider the overall safety of our customers and associates, including Mr. Casias, when making a difficult decision like this."

    Asked if Wal-Mart officials were considered offering Casias his job back, Rossiter replied: "No, we're not."

    The Marijuana Policy Project, a Washington-based marijuana advocacy organization, has called for a nationwide boycott of all Walmart stores to protest Casias' termination.

    "MPP is asking shoppers to demand that Wal-Mart abandon its discriminatory policy of firing employees who are legal medical marijuana patients under state law," an MPP blog posting read. "We need to send a strong message to Wal-Mart and other businesses in medical marijuana states that it is not acceptable to fire sick people for trying to get better by following their doctor’s recommendation and obeying state law. Marijuana is a legitimate medicine, supported by science and protected by law in 14 states, including Michigan."

    Dan Korobkin, a staff attorney for the American Civil Liberties Union's Michigan branch, said Wal-Mart's action against Casias is unlawful and "shameful."

    "It's illegal to fire somebody for being a medical marijuana patient, and it's also shameful to punish somebody for treating their medical condition in a legal way," Korobkin told FoxNews.com. "As far as I know, Wal-Mart itself sells a lot of over-the-counter drugs and prescription medications."

    Korobkin said federal authorities have announced they will not enforce federal marijuana laws in states that have legalized its usage for medicinal purposes, including Michigan, and he's "cautiously optimistic" that Wal-Mart officials will reconsider Casias' termination.

    "Wal-Mart is a large corporation, but they don't supersede state laws," he said. "When the voters of the state vote to make the use of medical marijuana legal and protected, that is a law that binds even Wal-Mart."