Q. We have an older friend who has a thing about mothballs. She uses them extensively throughout her house in every closet and around all the baseboards. When you walk in the door the smell is very strong. Can excessive mothball exposure be toxic? She is losing weight inexplicably and we are worried.
A. Mothballs used to contain naphthalene. Because this chemical was flammable, it has been phased out in favor of 1,4-Dichlorobenzene (para-Dichlorobenzene). A mothball is a compressed ball of chemical pesticide. As it volatilizes (turns into a gas) it liberates a chemical that is highly toxic to moths.
Mothballs can be toxic in excess. If children or pets swallow mothballs, poisoning may result in serious consequences including jaundice, anemia and kidney damage due to destruction of red blood cells. Parents must keep mothballs out of reach.
Long-term exposure to fumes is harder to assess. At high concentrations, symptoms such as eye irritation, weakness, dizziness, weight loss and liver problems have been reported.
What is less clear is lower-dose, chronic exposure. The Environmental Protection Agency states that:
“The primary exposure to 1,4-dichlorobenzene is from breathing contaminated indoor air. Acute (short-term) exposure to 1,4-dichlorobenzene, via inhalation in humans, results in irritation of the skin, throat, and eyes. Chronic (long-term) 1,4-dichlorobenzene inhalation exposure in humans results in effects on the liver, skin, and central nervous system (CNS). No information is available on the reproductive, developmental, or carcinogenic effects of 1,4-dichlorobenzene in humans. A National Toxicology Program (NTP) study reported that 1,4-dichlorobenzene caused kidney tumors in male rats and liver tumors in both sexes of mice by gavage (experimentally placing the chemical in their stomachs). EPA has classified 1,4-dichlorobenzene as a Group C, possible human carcinogen.”
We suspect that if you can smell the distinctive aroma of mothballs when you enter your friend’s house, she is exposing herself to too much pesticide.