WASHINGTON, April 8 (Reuters) - The U.S. Federal Aviation Administration on Wednesday proposed a $255,000 civil fine against American Airlines , alleging that the carrier violated employee drug- and alcohol-testing regulations.

On Friday, the FAA proposed a similar fine against Southwest Airlines.

On Wednesday, the FAA said that between May 2019 and December 2023, American allowed 12 flight attendants who had tested positive on drug and alcohol tests to resume performing safety-sensitive duties without completing all the required follow-up testing.

American said it was reviewing the FAA notice. "The safety of our customers and team members is paramount. We take drug and alcohol testing seriously and collaborate with the FAA to address any issues," the airline said in a statement.

On Friday, the FAA proposed a $304,000 fine against Southwest, alleging it failed to conduct required follow-up drug or alcohol testing for 11 employees, including pilots, flight attendants, and aircraft mechanics. 

The FAA said the employees previously tested positive for alcohol or drugs including marijuana, cocaine and amphetamines. The regulator said that during various periods between August 2021 and July 2024, the employees performed safety-sensitive functions when Southwest did not subject them to required follow-up testing.

Southwest said it takes seriously its drug and alcohol testing responsibilities and continues to engage with the FAA.

"We took immediate action more than two years ago to enhance our procedures and to strengthen oversight and accountability," the airline said.

Both airlines have 30 days to respond.