This is a fact sheet about a chemical that may be found in some public or
private drinking water supplies. It may cause health problems if found in
amounts greater than the health standard set by the United States
Environmental Protection Agency (EPA).
What is Asbestos and how is it used?
Asbestos is a fibrous mineral occurring in natural deposits. Because
asbestos fibers are resistant to heat and most chemicals, they have been
mined for use in over 3,000 different products, including roofing
materials, brake pads, and cement pipe often used in distributing water to
Why is Asbestos being regulated?
In 1974, Congress passed the Safe Drinking Water Act. This law requires
EPA to determine safe levels of chemicals in drinking water which do or
may cause health problems. These non-enforceable levels, based solely on
possible health risks and exposure, are called Maximum Contaminant Level
The MCLG for asbestos has been set at 7 million fibers per liter of
water (M.L.) because EPA believes this level of protection would not cause
any of the potential health problems described below.
Based on this MCLG, EPA has set an enforceable standard called a
Maximum Contaminant Level (MCL). MCLs are set as close to the MCLGs as
possible, considering the ability of public water systems to detect and
remove contaminants using suitable treatment technologies.
The MCL has also been set at 7 M.L. because EPA believes, given present
technology and resources, this is the lowest level to which water systems
can reasonably be required to remove this contaminant should it occur in
These drinking water standards and the regulations for ensuring these
standards are met, are called National Primary Drinking Water Regulations.
All public water supplies must abide by these regulations.
What are the health effects?
Short-term: Asbestos is not known to cause any health problems when
people are exposed to it at levels above the MCL for relatively short
periods of time.
Long-term: Asbestos has the potential to cause the following effects
from a lifetime exposure at levels above the MCL: lung disease; cancer.
How much Asbestos is produced and released to the environment?
Asbestos fibers may be released from natural sources such as erosion of
asbestos-containing ores, but the primary source is through the wear or
breakdown of asbestos-containing materials, particularly from the
wastewaters of mining and other industries, and by the use of asbestos
cement pipes in water supply systems.
From 1987 to 1993, according to the Toxics Release Inventory, asbestos
releases to water and land totaled nearly 9 million lbs. These releases
were primarily from asbestos products industries which use asbestos in
roofing materials, friction materials, and cement. The largest releases
occurred in Pennsylvania and Louisiana.
What happens to Asbestos when it is released to the environment?
As a naturally occurring substance, asbestos can be present in surface
and ground water. Small fibers may be carried long distances by water
currents before settling. Asbestos fibers do not bind to soils, but
nevertheless do NT migrate to ground water through soils. Asbestos is not
expected to accumulate in aquatic life.
How will Asbestos be detected in and removed from my drinking water?
The regulation for asbestos became effective in 1992. Between 1993 and
1995, EPA required your water supplier to collect water samples once and
analyze them to find out if asbestos is present above 7 M.L. If it is
present above this level, the system must continue to monitor this
contaminant once every 3 months.
If contaminant levels are found to be consistently above the MCL, your
water supplier must take steps to reduce the amount of asbestos so that it
is consistently below that level. The following treatment methods have
been approved by EPA for removing asbestos: Coagulation/Filtration, Direct
and Diatomite Filtration, Corrosion Control.
How will I know if Asbestos is in my drinking water?
If the levels of asbestos exceed the MCL, the system must notify the
public via newspapers, radio, TV and other means. Additional actions, such
as providing alternative drinking water supplies, may be required to
prevent serious risks to public health.
This is a factsheet about a chemical that may be found in some public
or private drinking water supplies. It may cause health problems if found
in amounts greater than the health standard set by the United States
Environmental Protection Agency (EPA).
Drinking Water Standards:
MCLG: 7 M.L. (million fibers per liter)
MCL: 7 M.L.
Asbestos Releases to Water and Land, 1987 to 1993 (in pounds):
|Top Five States*|
|Industrial organic chems
|Asphalt felts, coatings
* Water/Land totals only include facilities with releases greater than
a certain amount - usually 1000 to 10,000 lbs.
Note: This fact sheet is part of a larger publication adapted from U.S. EPA publication: EPA National Primary Drinking Water Regulations.