The test revealed that the controller was above the legal limit for blood-alcohol content, a limit that is lower for air traffic controllers than for automobile drivers.
The controller has since been removed from duty and is in an alcohol rehabilitation facility, KMGH reported.
This makes "dismissed" in the headline a false statement. He was removed from his duty.
We used to have a thing in the Navy called "a fitness for duty" drug test, which was under certain conditions adminstered when one had reason to believe that a sailor was unfit for duty based on chemical impairment.
Not all drug tests need be random.
Hopefully, this experienced controller can be brought back into the fold via rehab/substance abuse remedy. It may or may not be possible. Each case has its own quirks.