Discarded pepper spray or Mace was the likely culprit in a chemical alarm Tuesday morning at the Minneapolis-St. Paul International Airport that sent 19 workers to area hospitals.
Shortly before 11 a.m., Transportation Security Administration officers, or security screeners, complained about irritation to the eyes, nose and mouth, said Patrick Hogan, spokesman for the Metropolitan Airports Commission.
The area around Security Checkpoint One in the Lindbergh terminal was evacuated and closed for several hours as multiple air tests were conducted.
Ticketing counters for American Airlines and US Airways were temporarily set up curbside, leading to longer lines of travelers. Hogan said nothing was found in the tests. The area reopened about 4 p.m. Tuesday.
Some people reported seeing a cloud of dust near the checkpoint, Hogan said.
Sixteen officers and three employees at US Airways' ticketing station were taken to three hospitals. All were treated and released by late Tuesday afternoon, said TSA spokeswoman Carrie Harmon and airline representatives.
One traveler who went through the checkpoint was treated about 11:30 a.m. on Concourse E for similar symptoms but refused to be taken to a hospital, Hogan said.
No sign it was deliberate
Separate air tests conducted by the Metropolitan Airports Commission and St. Paul fire departments as well as the Minnesota National Guard found nothing, he said.
"They could find absolutely no sign of air contamination," he said. "It's important that people recognize that we don't have any indication that this was a deliberate act to disrupt airport operations."
Given the workers' symptoms and that the air tests did not find anything, Hogan said, the likely culprit is discarded Mace or pepper spray. Travelers often carry the chemicals and forget about them until they enter a checkpoint, he said. The chemicals are prohibited past the checkpoint.
An airline employee who worked nearby did turn over an empty pepper spray can, Hogan said. She told authorities she had not set it off, he said, and there is no indication it caused the irritation.
The incident remains under investigation. Surveillance video at the checkpoint will be reviewed, Hogan said.
"At this point, there's no reason to believe there was any foul play," he said.
Terri Dresen, spokeswoman for United Hospital in St. Paul, said the four patients from the airport brought there had minor respiratory problems, including wheezing.
They were stripped down and hosed off in an emergency decontamination unit set up in the garage to isolate them from other patients, she said. X-rays were taken and blood was drawn as part of their examination. Dresen said the patients all reported a slow progression in breathing difficulty.
One US Airways flight to Phoenix was delayed about an hour, said the airline's spokeswoman, Valerie Wunder.
She and American Airlines spokesman Tim Wagner did not report other flight delays.
Ann Zeiss, returning to Los Angeles on an American Airlines flight, said she wasn't particularly fearful despite recent terrorism scares.
"I think it's important that people keep flying," she said.
Harmon said she could not recall similar incidents at other airports across the nation, although she noted that there have been smaller, isolated cases of travelers' items that have affected screeners. She said travelers should check the TSA website, , for a list of prohibited items.
All the screeners were in good condition Tuesday, Harmon said.
Hogan also could not recall similar incidents at the airport or elsewhere. There was a scare in July when police dogs reacted separately to scents at an automated teller machine and a soft-drink vending machine. That prompted the evacuation of several hundred people from the Humphrey terminal for nearly four hours.
The machines were dismantled, and nothing was found. At the time, authorities speculated that gunpowder or fireworks residue was the cause because of the recent July 4th holiday.