Clean-smelling rooms may come at a price: Lung damage

It may not be a household name, but 1,4-dichlorobenzene is a common household smell. It is the whiff of mothballs, the aroma masking a damp basement, the essence of an under-ventilated bathroom. It comes from a solid brick of insect-chasing, odor-covering, toilet-bowl cleaning power called paradichlorobenzene -- or “para” in the cleaning trade.

A new study says the chemical could be damaging the lungs of people who inhale it regularly.

When exposed to air, paradichlorobenzene (what mothballs are made of) gives off a volatile organic compound -- a chemical emitted in gas form -- called 1,4-dichlorobenzene (or, in chemical shorthand, 1,4-DCB). It is not one of those airborne compounds -- benzene, styrene and toluene -- whose names have long prompted shudders of concern among experts in air quality. In fact, in the latest study of volatile organic compounds and lung function, published in the August issue of Environmental Health Perspec- tives, those compounds came off looking pretty innocent by comparison.

Of 11 such compounds found in detectable concentrations in the blood of the latest study’s participants, only one -- 1,4-DCB -- was associated with poorer lung function.

Dr. John Balmes, a pulmonary critical care physician and professor of medicine at UC Berkeley and UC San Francisco, said he was surprised by the study. But Balmes, also a spokesman for the American Lung Assn.’s California chapter, added that the new finding was in line with several studies that have warned of the respiratory dangers of many household cleaners.

He says that when his patients ask about air fresheners in general, “I’d say if you can avoid it, not to use them. I don’t see the need to introduce other chemicals into our environment when there’re already so many bad actors.”

A study released in May by the California Air Resources Board, a division of the state’s Environmental Protection Agency, warned that several compounds found in air fresheners and household cleansers can reach harmful concentrations inside homes. But the blocks of “para,” found in slow-dissolving air fresheners and toilet-bowl deodorizers, pose a particular problem because they release compounds into the air over a long period. The result is that exposure to these fumes is, by design, chronic.

In the latest study, researchers from the National Institute of Environmental Health Sciences drew from measurements taken in an extensive national health survey conducted between 1988 and 1994. In all, 1,018 Americans were tested both for exposure and lung function, and 846 showed blood levels of 1,4-DCB suggestive of some chronic exposure. In two key measures of respiratory function, those with exposure to the “para” fumes tested more poorly, and their respiratory function declined as exposures among participants increased. Even among study participants who never smoked, the relationship between exposure to 1,4 DCB and lung impairment was significant. While such reductions in lung function can be temporary when they are the result of a short exposure to harmful substances, the authors noted that “they generally precede permanent effects.” And when a person sustains permanent lung damage, he or she is at higher risk for heart disease, stroke and cancer.

Anthony Tran, president of a small Los Angeles-based cleaning company, said he had grown more concerned, both for his clients’ health and that of his 12 employees. As a result, he said, his family’s company, Sunset Cleaners, expects to discontinue a wide range of harsh cleaning agents and replace them with gentler cleaning solutions that, in many cases, have been used for hundreds of years.

“I’m definitely making a point of paying attention to the products I use now,” Tran said. “It’s a new type of thinking.”