Daily News Archive
From February 2, 2001

NIH Study Finds Moth Ball Pesticide to be Carcinogenic

In its 500th two-year safety test of chemicals in rodents, the National Institute of Environmental Health Science's National Toxicology Program (NIEHS-NTP), part of the National Institutes of Health (NIH), found that naphthalene, the principal ingredient in mothballs, causes cancer in laboratory rats. In the study, rats were exposed by inhalation, just as most people are, in doses comparable to some human consumer and workplace exposures.

NIEHS-NTP Study Scientist Kamal Abdo said naphthalene was nominated for study by the National Institute of Occupational Safety and Health, the Occupational Safety and Health Administration, and the U.S. Environmental Protection Agency (EPA) - all of which are represented on the NTP Executive Committee - after German workers exposed to naphthalene were found to have a variety of cancers - including laryngeal, gastric, nasal, and colon cancer. EPA will have the opportunity to review the study and current labeling and take regulatory action as appropriate, using other studies and data as well.

The most widely known use of naphthalene is in mothballs and bathroom deodorizers, but it also has a number of chemical manufacturing uses, and is used in veterinary medicine to control lice and as a disinfectant for lesions and incisions. It enters the human food chain when used on livestock that then ingest or inhale it. Naphthalene can also be absorbed easily through the skin and is a known irritant. Parents of newborns are especially cautioned because studies have shown reactions including acute hemolysis, jaundice and death in infants wrapped in blankets that had been stored with moth balls over the summer.