About 30,000 federal transportation employes were notified yesterday they must participate in random drug testing, the Transportation Department said.

Employes involved in safety or security jobs were sent notices that their names have been placed in a pool and that they will have an equal probability of being selected for random testing.

The department is the first federal agency to act on President Reagan's executive order calling for drug testing of federal employes. The sweeping drug-testing program was announced by Transportation Secretary Elizabeth Hanford Dole last January.

Gary DiNunno, a spokesman for the American Federation of Government Employes, said the AFGE will seek an injunction to prevent drug testing. The union sued the Transportation Department last month after the department issued a memorandum June 29 notifying employes that the drug-testing program would begin by the end of the summer.

"It's my understanding most of the employes have not re- ceived their notices yet," DiNunno said.

"My guess is people won't receive them until the beginning of next week," he said. "Then we will go to court to block drug testing until there is a hearing on the merits of our case."

Dole said in a statement that employes will be tested for marijuana metabolites, cocaine metabolites, opiates, phencyclidine (PCP) and amphetamines.

The drug testing will be performed through urinalysis by an independent contract laboratory. The program involves an initial screening, which would be followed by a confirmation test and review of any positive laboratory results, Dole said.

Among the employes to be tested are air traffic control specialists, flight test pilots, civil aviation security specialists, aviation safety inspectors, railroad safety inspectors, Coast Guard drug enforcement officers, fire fighters and Transportation Department employes with a security clearance of top secret or higher.

Employes who test positive will be removed from their positions and reassigned.

Of those who test positive, employes found to have used drugs during off-duty hours will be offered a chance to seek counseling or participate in the department's drug rehabilitation program. Employes found to have used drugs while working will be fired.

Not all of the 30,000 will be tested. Those tested once may be tested again because their names will remain in the pool.