FORT MCMURRAY, Alta. -- Oilsands giant Suncor Energy has lost another battle in its attempt to randomly test thousands of union workers in northern Alberta for drugs and alcohol.

A court-ordered arbitration panel has sided with the union Unifor that represents 3,600 workers in the Fort McMurray area and which had filed a grievance against the policy.

The majority of panel members ruled there is no evidence that there is an out-of-control drinking or drug culture at Suncor (TSX:SU).

The panel said the random testing policy is an unreasonable exercise of Suncor's management rights.

Suncor says it will ask the Alberta Court of Queen's Bench for a judicial review of the ruling.

The union says it will work with Suncor to improve workplace safety through education and prevention programs.