Asking for bottled water or a canned drink aboard an airliner might be the safest way to fly.
Coliform bacteria are showing up in more airliners than last summer when the government first took steps toward requiring sanitation improvements.
The Environmental Protection Agency will now have domestic airlines test themselves and submit results to the agency to see if the trend continues. Some self-sampling has begun, and airlines are adapting their routine disinfections to meet EPA guidance.
Airlines now must disinfect water systems every three months and water carts and hoses leading to aircraft monthly.
Coliform bacteria, usually harmless, indicate that harmful organisms could be present. EPA said Wednesday it found coliform bacteria in 17 percent of the airliners it randomly tested in November and December, an increase from the 13 percent reported in the first round of tests in August and September.
Lavatory faucets and galley water taps
Among 169 randomly tested airliners, most of the 29 that tested positive for coliform bacteria had them in lavatory faucets, but some also had them in galley water taps. There were no cases of the more serious E. coli bacteria, which can cause diarrhea and nausea, an improvement from two cases found in previous testing.
Lab testers typically analyze for “total coliform” — whether coliform bacteria are present — and then recheck the sample to find out if coliform bacteria are of fecal origin and whether E. coli are present.
The Air Transport Association, representing the major airlines, said “airline drinking water is as safe as the municipal water sources that supply it.”
“We believe the most significant finding by the EPA is that there were no positive tests for any harmful bacteria,” said Nancy Young, managing director of Washington-based ATA’s environmental programs.
The latest round of aircraft testing came from planes ranging from small commuter aircraft to jumbo jets at 12 airports. The coliform bacteria were found at planes in Fort Lauderdale, Fla.; Newark, N.J.; Miami; Phoenix; Los Angeles; and Santa Ana, Calif. Results were not available for two airports in Houston.
EPA advised passengers with compromised immune systems or others concerned with the quality of onboard water to ask for canned or bottled beverages and to refrain from drinking tea or coffee unless made with bottled water.
“It’s not an indication that anyone needs to panic, it’s not an indication that anyone shouldn’t fly,” said Thomas V. Skinner, acting assistant administrator for EPA’s Office of Enforcement and Compliance Assurance. “But it’s an issue that’s of concern. I think it’s of concern to both us, and should be to the airlines as well, and we are committed to working through the issue.”
EPA’s tests last August and September found coliform bacteria on 20 of the 158 randomly selected aircraft.
In November, EPA and 12 major airlines agreed on a program aimed at improving sanitation. It included more testing and disinfection of aircraft.
Signing agreements with EPA were Alaska Airlines, Aloha Airlines, American Airlines, America West, ATA Airlines, Continental Airlines, Hawaiian Airlines, JetBlue, Midwest Airlines, Northwest Airlines, United Airlines and U.S. Airways.
Two other airlines, Delta Airlines and Southwest Airlines, are negotiating separate agreements.