Of the 500 who tested positive, 208 recovered from the illness caused by the coronavirus, the agency said in a statement.
Almost 40 percent of positive cases were found in employees working in the three major airports serving the greater New York City region.
At John F. Kennedy International Airport, in Queens, 105 employees tested positive. At LaGuardia Airport, also in Queens, 32 tested positive. Newark Liberty International Airport in New Jersey had 56 positive cases.
Other airports near the top of the list include Louis Armstrong New Orleans International Airport (27), Miami International Airport (18), Denver International Airport (17) and O'Hare International Airport in Chicago (15).
Major West Coast airports had fewer cases, according to the TSA.
Los Angeles International Airport had 11 positive cases, while Seattle-Tacoma International Airport had six. San Francisco International Airport had two.
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The data provided by the TSA did not include employees of the agency who do not work in airports or who have limited interaction with the public.
Air travel in the U.S. has cratered because of the coronavirus pandemic. Airlines for America, an industry lobbying group that represents Southwest and other major carriers, said this month that passenger volume is down by 97 percent to a level not seen since 1954.