Claimant tested positive for cocaine metabolites during a return-to-work physical examination on March 22, 1990. He did, at that time, have a choice. He could furnish a negative sample within a specified time period or enter a rehabilitation program.

He chose the former and furnished a negative sample. He was allowed to return to work, but as a condition of his return, he agreed in writing to be randomly tested and to keep his "system free of such substances."

On March 1, 1993, Claimant underwent another return-to-work physical, which included a test for drugs. Once again, he tested positive for cocaine metabolites. A Notice of Investigation was timely issued and following the Investigation, Claimant was dismissed from service.

The Organization challenges Carrier's decision to dismiss on various grounds, namely: (1) that Carrier failed in its burden of proof (2) the drug tests used were unreliable and (3) that Carrier failed to consider the "prescribed medication" Claimant was taking that could possibly have caused the positive test.

This Board examined the entire record, the transcript and onproperty exchange of correspondence rela of the opinion the Organization's attack on this discipline procedure is for naught.

Carrier was not able to consider the effects of the prescribed medication the physician used in swabbing Claimant's infected tonsil as Claimant himself could not provide the Carrier with even a clue as to identifying the medicine, other than to speculate that it was an antibiotic.

Regarding the burden of proof and unreliable drug test arguments, a review of the transcript and supporting documentation convinces this Board that these two arguments are without merit.

In 1990 Claimant was allowed to return to service under specific agreed to conditions. He failed to abide with the terms of the agreement he signed. The discipline of dismissal imposed by the Carrier will not be disturbed.

AWARD