Deck the halls with DCA

A plastic ornament was caught giving off poisonous vapors


Doucette and his team scratched the surface (and amputated the legs) of this ornament to find the source of its toxic emissions.


W. Doucette

You can bet Santa Claus would have something to say about this: Earlier this year, a team of chemists visited a basement in a house in Utah, looking for trouble.

And they found it — in the form of a gingerbread man. It wasn’t a real; it was a Christmas ornament. The scientists took the ornament back to the laboratory, where they chopped it up and studied the pieces. They found poison.

No matter how it sounds, the chemists aren’t the bad guys: Unlike Lord Farquaad in Shrek, who cut off the gingerbread man’s legs to keep him from running away, the scientists weren’t being naughty. Instead, they were trying to help the people who lived in the house.

Bill Doucette led the study of the gingerbread man. He is a chemist at Utah State University. At first, he and his team weren’t looking for Christmas ornaments. They had been called to Hill Air Force Base, near Salt Lake City, to investigate high indoor levels of dangerous chemicals in air. At a recent meeting of scientists and journalists in New Orleans, Doucette discussed how the team found the gingerbread man.

The researchers already knew that the Air Force base pollutes an underground water supply with these chemicals. They also knew that gases from the polluted water can rise through the ground and get into houses. Most of the houses are protected against this pollution, however, so Doucette and his team suspected something else was causing the problem.

In one of the houses where the gases had been detected, the chemists’ search for the source had led them to the basement. And in the basement, they found out where the vapors were coming from: A box of Christmas ornaments. They took the ornaments back to the lab and found that the ornaments had a dangerous chemical called DCA.

Scientists also know DCA by its chemical name, 1,2-dichloroethane. As a colorless, sweet-smelling liquid, DCA is used in the production of plastics. But, as the chemists discovered, the DCA used in the ornaments can also leak DCA gas, or vapor, into the air.

The gingerbread man was made of molded plastic that had been made with DCA. In every gram of the plastic, the chemists found 2.3 milligrams of DCA. That’s roughly two parts in a thousand (imagine two blue gumballs in a gumball machine with 1,000 white gumballs). That may not sound like much, but it’s enough to pollute the air to unsafe levels.

When people are exposed to high levels of DCA, particularly in drinking water, they may suffer problems with their lungs, kidneys or stomach. Long-term exposure has been linked to cancer, according to the Environmental Protection Agency. In their study of the Christmas ornaments, Doucette and his colleagues found that just one gingerbread man ornament raised the DCA levels in a house to unsafe levels.

Doucette and his team tested a variety of ornaments, and in nearly every case the ornaments that produced DCA were labeled “made in China.” United States companies are not allowed to use DCA in the production of consumer goods — things like food and clothing that people use every day — said Christina McNaughton.

McNaughton was also at the New Orleans meeting. She works at the Utah Department of Health in Salt Lake City and says that ornaments aren’t the only problem — other products are made from the same material. “It’s not just a holiday phenomenon,” she said. It’s also not just Utah’s problem: Across the country, scientists have been finding high levels of DCA — and finding danger in unexpected places, like Christmas ornaments. Government agencies, like the U.S. Consumer Product Safety Commission, have started to investigate, McNaughton said. And she said she hopes to start testing many products for DCA.

“This is something that’s definitely going to affect a lot of people,” McNaughton predicted. There is a bright side, however. Once scientists identify the sources of DCA, they can recommend changes that can improve people’s health — a goal that will get anyone on Santa’s good list.

Stephen Ornes lives in Nashville, Tenn., and his family has two rabbits, six chickens and a cat. He has written for Science News Explores since 2008 on topics including lightning, feral pigs, big bubbles and space junk.

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