A cocaine-addicted truck operator fired from his job at an Alberta coal mine cannot claim discrimination over his dismissal, the Supreme Court of Canada ruled Thursday.

In an 8-1 decision, the country's highest court upheld lower court rulings, saying Ian Stewart was fired for breaching his employer's drug policy, not because of his addiction.

Stewart drove a loader at a mine operated by the Elk Valley Coal Corp., which owns five mines in B.C. and the Cardinal River mine south of Hinton in Alberta. Stewart had worked for the company for nine years.

"The mine operations were dangerous and maintaining a safe worksite was a matter of great importance to the employer and employees," the court said in its decision.

Stewart's loader collided with another truck on the worksite in October 2005.

After testing positive for drug use, Stewart admitted to company officials he used cocaine on his days off and said he thought he was addicted to cocaine. He said that before the collision, he had been in denial about the addiction.

Elk Valley Coal fired him.

Company policy breached

Stewart appealed to the Alberta Human Rights Tribunal, arguing he was discriminated against on the basis of a disability, namely an addiction, contrary to Section 7 of the Alberta Human Rights, Citizenship and Multiculturalism Act.

The tribunal held that Stewart was terminated for breaching the policy, not because of his addiction. The decision was affirmed by the Alberta Court of Queen's Bench and by the Alberta Court of Appeal.

The Supreme Court also agreed.

Chief Justice Beverley McLachlin wrote that while Stewart "may have been in denial about his addiction, he knew he should not take drugs before working and had the ability to decide not to take them, as well as the capacity to disclose his drug use to his employer.

"Denial about his addiction was thus irrelevant in this case."

In his dissenting opinion, Justice Clement Gascon said the company did not go far enough to accommodate Stewart's addiction.

"None of the employer's efforts at accommodation provided [Stewart] with accessible accommodation during his employment, and those efforts failed to consider his individual circumstances in a dignified manner, so the employer cannot be said to have discharged its duty to accommodate him as an employee up to the point of undue hardship."

The appeal was dismissed.