Name: Arlene Bennett
Date: Around 1999
My mother in law uses moth balls for everything. She has
them in every drawer, under the chesterfield, in all the closets, under
every bed, and in every corner, just to make sure, of what I don't know.
There is a distinct odor of moth balls as soon as you enter the house,
and if we bring anything home to our house to ours, the smell comes with
it, even food she has given us from her fridge, which worries us, since
the smell is even penetrating the food behind a sealed door. I'm worried
if it is a chemical and is it at all toxic? Could it be dangerous used to
this extent? Is it a repellent like in DDT? I would appriciate an answer,
thank you very much. I have now bookmarked this web page,it is so helpful
to find the answers to an important question to ease one's mind.
Moth balls are not all made of the same substance. Common chemicals used
for moth balls are naphthalene, p-dichlorobenzene, and camphor. These
compounds have different toxicities, but none of them are exactly vitamins.
And I certainly wouldn't enjoy eating food that smells like moth balls; I
don't find it a pleasant smell. At least, moth balls don't smell like
anything I want to eat.
According to the Merck Index, the actual acute toxicity of
p-dichlorobenzene isn't very high; it takes 500 milligrams per kilogram of
body weight to kill half the exposed rats. The hazardous effects of
p-dichlorobenzene vapors are "irritation to skin, throat, and eyes.
Prolonged exposure to high concentrations may show weakness, dizziness,
loss of weight; liver injury may develop." I don't know how high they
mean, and I certainly don't know what the levels might be in your
mother-in-law's house, but if she's in her house a lot, and the whole place
smells like moth balls, chances are that it will do her some harm over
time. Of course, there are many different reasons for people to get sick.
The mothballs should certainly be mentioned to her doctor if she's having
some sort of trouble.
I don't have numbers for the toxicity of naphthalene. Routes of exposure
to toxic amounts are inhalation, ingestion of large doses, and absorption
through the skin. Symptoms and signs of naphthalene poisoning are nausea,
vomiting, headache, diaphoresis (whatever that is), hematuria, hemolytic
anemia, fever, hepatic necrosis, convulsions, and coma.
Camphor is somewhat less toxic than p-dichlorobenzene (3000 milligrams per
kilogram). The Merck Index does not list toxic effects of inhalation, only
ingestion or injection, which are not exposure routes that are likely to be
important fom mothballs in the house. So I'm confident in saying that
camphor is less hazardous to humans than naphthalene or dichlorobenzene.
Incidentally, DDT is not a repellent, it is an insecticide. It kills bugs
dead, but it is not very toxic to humans at all. That is why it was so
widely used at first - it was much safer to administer than the previous
insecticidal agents, such as paris green and lead arsenate. It turned out
to interfere with the production of birds' eggshells, which made it hard
for them to reproduce.
Richard Barrans Jr., Ph.D.
Chemical Separations Group
Argonne National Laboratory
Click here to return to the Chemistry Archives
Update: June 2012