Benzene study in Anchorage targets attached garages

Because of our gasoline and our climate, Alaskans who live in homes with attached garages are at higher risk of exposure to harmful chemicals in the air. A few scientists are trying to find out the size of that risk.

Mary Ellen Gordian of Anchorage is a physician and a professor at the University of Alaska Anchorage who is beginning a study of benzene levels in which she hopes to test 400 local homes. In a preliminary study of Anchorage homes with attached garages, she found that one-third of the air samples from those homes had unhealthy levels of benzene.

“We had families exposed to levels way above the minimal risk level for acute exposure, and they’re being exposed to it 24-7 because it’s in their home,” she said.

Doctors have linked benzene to a higher risk of cancer related to white blood cells, such as leukemia and lymphoma, and Gordian suspects there may be a link between benzene exposure and asthma. Alaskans have a higher risk of exposure to benzene because gasoline refined here from North Slope crude oil has a higher proportion of benzene than gas produced in the Lower 48, Gordian said.

“We’re the only place that uses gas with about five percent benzene in it,” she said, adding that smog regulations in the Lower 48 require that gasoline have one percent or less benzene. “We don’t have to take it out because we don’t have their smog problem, and (the extra benzene) helps in cold starts. It’s very volatile.”

Gordian is hoping to enlist 400 people in Anchorage to help her with the city’s study this winter, and will soon mail out invitations for the study to Anchorage families she will select randomly.

She thinks the study is important because almost every new house built in Anchorage has an attached garage and a forced-air furnace, and because gasoline-powered items stored in attached garages tend to leak vapors into the air that can migrate into the house. During a study done in Anchorage in 2004, University of Washington researchers, working with Steve Morris of the Municipality of Anchorage, found that about 27 percent of the air coming into a house was from the attached garage, and the rest from outside. They also found more contaminants in indoor air during winter than in summer, unlike the results of a smaller Fairbanks study I reported on a few weeks ago.

“It’s a quandary,” said John Freeman of Sunrise Energy Works in Anchorage, whose job sometimes includes performing studies of indoor air pollution. “We’ve got a longer season of being closed up, and gas with more pollutants in it.”

Freeman once conducted an experiment in which he found that carbon monoxide emitted from cars made its way into the living space of homes shortly after someone started the car. He said the problem occurs most dramatically in homes with forced-air furnaces, but also in homes with boilers in the garage. A new building code that required less leakage of ductwork in the furnace systems could reduce the transfer of pollutants. For those with existing systems, it makes sense to store fewer gasoline-powered engines in attached garages.

“Reducing the amounts of gas and engines in your garage will reduce the amount of benzene you’re exposed to,” Gordian said.