Also known as: Polynuclear Aromatic Hydrocarbons,
Examples: Benzo(a)pyrene, Benzanthracene, Benzo(b)fluoranthene,
What are PAHs?
PAHs are a group of approximately 10,000 compounds, a few of which are listed above.
Most PAHs in the environment are from incomplete burning of carbon-containing materials
like oil, wood, garbage or coal. Many useful products such as mothballs, blacktop, and
creosote wood preservatives contain PAHs. They are also found at low concentrations in
some special-purpose skin creams and anti-dandruff shampoos that contain coal tars.
Automobile exhaust, industrial emissions and smoke from burning wood, charcoal and
tobacco contain high levels of PAHs. In general, more PAHs form when materials burn at low
temperatures, such as in wood fires or cigarettes. High-temperature furnaces produce fewer
Fires can form fine PAH particles. They bind to ash particles and can move long
distances through the air. Some PAHs can dissolve in water. PAHs can enter groundwater
from ash, tar, or creosote that is improperly disposed in landfills.
How are people exposed to PAHs?
Breathing: Most people are exposed to PAHs when they breathe smoke,
auto emissions or industrial exhausts. Most exhausts contain many different PAH compounds.
People with the highest exposures are smokers, people who live or work with smokers,
roofers, road builders and people who live near major highways or industrial sources.
Drinking/Eating: Charcoal-broiled foods, especially meats, are a
source of some PAH exposure. Shellfish living in contaminated water may be another major
source of exposure. PAHs may be in groundwater near disposal sites where construction
wastes or ash are buried; people may be exposed by drinking this water. Vegetables do not
take up significant amounts of PAHs that are in soil.
Touching: PAH can be absorbed through skin. Exposure can come from
handling contaminated soil or bathing in contaminated water. Low levels of these chemicals
may be absorbed when a person uses medicated skin cream or shampoo containing PAHs.
Do standards exist for PAHs?
Water: Wisconsin has established drinking water standards for five
PAHs: Anthracene - 3,000 parts per billion (ppb), Benzo(a)pyrene - 0.2 ppb,
Benzo(b)fluoranthene - 0.2 ppb, Fluoranthene - 400 ppb and Fluorene - 400 ppb. We suggest
you stop drinking water containing more than these amounts. If other PAHs are found in
your drinking water, contact your local public health agency for advice.
Air: No standards exist for the amount of PAHs allowed in the air of
homes. We use a formula to convert workplace limits to suggested home limits. Based on the
formula, we recommend levels of PAHs in air be no higher than 0.004 parts per million
The Wisconsin Department of Natural Resources regulates the amount of several PAHs that
can be released by industries.
Will exposure to PAHs result in harmful health effects?
The effects of breathing high concentrations of PAHs have not been studied. However,
PAHs may be attached to dust or ash causing lung irritation. Skin contact with PAHs may
cause redness, blistering, and peeling.
The following health effects can occur after several years of exposure to PAHs:
Cancer: Benzo(a)pyrene, a common PAH, is shown to cause lung and skin
cancer in laboratory animals. Other PAHs are not known to have this effect. Extracts of
various types of smoke containing PAHs caused lung tumors in laboratory animals. Cigarette
smoke will cause lung cancer.
Reproductive Effects: Reproductive problems and problems in unborn
babies development have occurred in laboratory animals that were exposed to
benzo(a)pyrene. Other PAHs have not been studied enough to determine whether they cause
Organ Systems: A persons lungs, liver, skin, and kidneys can be
damaged by exposure.
In general, chemicals affect the same organ systems in all people who are exposed.
However, the seriousness of the effects may vary from person to person.
A person's reaction depends on several things, including individual health, heredity,
previous exposure to chemicals including medicines, and personal habits such as smoking or
Its also important to consider the length of exposure to the chemical; the amount
of chemical exposure; and whether the chemical was inhaled, touched, or eaten.
Can a medical test determine exposure to PAHs?
Many PAHs can be detected in blood or urine soon after exposure. Tests for these
compounds are not routine and can only be performed using special equipment not usually
found in doctor's offices. People who think they may have been exposed to PAHs for a long
time should contact their physician. Blood tests of liver and kidney function are
available. People exposed to PAHs in air may want to ask their doctor to consider having
lung function tests done.
Seek medical advice if you have any symptoms that you think may be related to chemical
(P-44606 Revised 12/2010)
This fact sheet summarizes information about this chemical and is not a complete
listing of all possible effects. It does not refer to work exposure or emergency
PDF: The free Adobe Reader®
software is needed to view and print portable document format (PDF) files.
Back to Toxic Chemical Fact Sheet