Environmental Health News

What's Working

  • Garden Mosaics projects promote science education while connecting young and old people as they work together in local gardens.
  • Hope Meadows is a planned inter-generational community containing foster and adoptive parents, children, and senior citizens
  • In August 2002, the Los Angeles Unified School District (LAUSD) Board voted to ban soft drinks from all of the district’s schools

#314 - Cement And Kiln Dust Contain Dioxins, 01-Dec-1992

During routine preparation of a REPORT TO CONGRESS ON CEMENT KILNS, the
U.S. Environmental Protection Agency (EPA) has learned that cement and
cement kiln dust contain dioxins and furans (both of which are powerful
poisons in animals and humans), according to a briefing document dated
October 8, 1992, prepared by EPA staff for EPA's Director of Solid
Waste, Sylvia Lowrance. The October briefing document also says 20
percent of the cement kiln dust that EPA tested contains the non-
natural radioactive elements plutonium-238, plutonium-239 and cesium-
137. Dioxins are the most powerful carcinogens (cancer-causing agents)
ever tested in laboratory animals; plutonium is the most potent
carcinogen in humans ever discovered.

Cement is a principal component of pipe often used to distribute
drinking water in many American cities. Cement kiln dust is a byproduct
of cement manufacture and is routinely given or sold to farmers as a
soil treatment, or is discarded into pits or is piled on the ground
near cement kilns in an uncontrolled fashion. According to Bill
Schoenborn, an EPA staff member working on the REPORT TO CONGRESS,
about 6 million tons of kiln dust is disposed of each year by cement
kilns, 5.1 million tons of it buried on-site, and 900,000 tons of it
shipped off-site for use in stabilizing other wastes (such as sewage
sludge) or as a soil additive on farms. Cement kiln dust has previously
been reported to contaminate groundwater with the toxic metals lead and
chromium,[1] but until now no one has reported dioxins, furans,
plutonium or cesium-137 in cement or cement kiln dust.

The REPORT TO CONGRESS is required by the federal Resource Conservation
and Recovery Act (RCRA), the nation's basic hazardous waste law. Like
mine wastes, cement kiln dust was initially exempt from RCRA because it
is a high-volume waste presumed to be low in toxicity. Cement clinker
(that is to say, cement itself) is exempt from RCRA because it is a
product, not a waste. Section 8002(o) of RCRA required EPA to study
cement kiln dust and to write a report for Congress on its findings.
For several years, EPA dragged its feet preparing the report. Then
Environmental Defense Fund (EDF) brought a lawsuit, and now EPA is
under a court order to finish the report by April, 1993.

In the course of preparing the REPORT TO CONGRESS, EPA randomly
selected 15 cement manufacturing plants (called kilns) for sampling,
out of the 114 such plants presently operating in the U.S. Of the 15
plants sampled, eight burn hazardous waste as fuel and seven do not. In
recent years, cement kiln operators have increasingly been using
hazardous waste as fuel, to reduce fuel costs and thus increase
profitability. The practice has proved controversial. (See RHWN #174
and #243.) Opponents of the practice say they fear cement will become
contaminated with industrial poisons. Cement is a key raw material in
concrete pipe for water delivery systems, and in concrete block and
other concrete materials used in construction of private homes,
commercial dwellings, public buildings, bridges and highways. Seventy
to 80 million tons of cement are produced in the U.S. each year,
depending on market demand.

Sampling Results

EPA took 15 samples of "clinker" (the product of a kiln, from which
cement is made), plus 28 samples of dust (the unwanted byproduct of a
kiln). All samples were analyzed for metals, chloride, cyanide,
fluoride, total sulfate, total organic carbon, moisture content, and
radioactive elements.

Samples from six kilns (4 burning hazardous waste, 2 not burning
hazardous waste) were tested for dioxins and furans, volatile organic
compounds, semivolatile organic compounds, and pesticides. All chemical
analyses were completed by EPA's National Air and Radiation
Environmental Laboratory (NAREL) in Alabama.

Dioxins and furans were detected in all samples of "clinker" and all
samples of kiln dust analyzed for these compounds. The October briefing
document says that the dioxin molecule known as 2,3,7,8-TCDD, the most
potent poison in the dioxin family, was only identified in samples from
kilns burning hazardous waste. Other dioxins were found in samples from
kilns not burning hazardous waste, but no 2,3,7,8-TCDD. However, the
October briefing document says it is not possible to generalize these
differences to the entire 114 operating cement kilns.

Samples of cement kiln "clinker" did not contain pesticides or
semivolatile organics. Clinker was not analyzed for volatile organics.
On the other hand, cement kiln dust contained amounts of the volatile
organics benzene and acetonitrile that exceeded RCRA limits "in a
number of the samples of hazardous waste burners" but not in samples
from kilns not burning hazardous wastes. The dust from one kiln not
burning hazardous waste proved to be high in methylene chloride,
according to the October briefing document.

These findings lend support to the view that burning hazardous waste in
a cement kiln increases the amount and potency of toxins in the
resulting cement kiln dust and perhaps in the cement itself.

At three kilns (2 burning hazardous waste, one not burning hazardous
waste) levels of naturally-occurring radioactive radium-226 exceeded
the cleanup standard for uranium mine and mill wastes (the standard
being 5 picoCuries per gram). Cesium-137, a non-natural radioactive
element, was present in the dust of 26 percent of the kilns tested (4
out of 15)--one hazardous waste burner and three non-hazardous waste
burners. Plutonium-238 and plutonium-239 were detected in kiln dust
samples from 3 of the 15 kilns tested. Each of these 3 facilities is
"located near a DOE [U.S. Department of Energy] nuclear weapons
production/testing facility," according to EPA's October briefing
document. Plutonium and cesium-137 do not occur in nature but are
created by nuclear bomb explosions and in nuclear power reactors.

A second EPA briefing document dated November 24, 1992, contains
additional information about the problem of potent toxins being found
in cement and in cement kiln dust. The document is titled "OSW Office
Briefing on Cement Kiln Dust Risk Screening" and it contains a summary
of a risk assessment that is being conducted by the EPA's
Communications and Budget Division within the Regulatory Analysis
Branch, Office of Solid Waste.

The November briefing document outlines two risk assessment scenarios:
one in which cement dust blows off-site and affects a person living 750
feet from an active waste pile, and a second in which an individual is
presumed to be living on top of an abandoned waste pile. No risk
assessment was reported for the case of a farmer growing crops in soil
to which cement kiln dust has been added.

Furthermore, no risk assessment is reported for the dioxins and furans
measured in cement clinker, which it to say, in cement itself.

Based on the two risk assessment scenarios, the November briefing
document describes amounts of toxins in cement kiln dust that appear to
be acceptable, which is to say will only give cancer to one in 100,000
individuals so exposed. The November document lists 22 instances in
which one or more EPA tests of cement kiln dust exceeded the criteria
developed in the risk assessments. Criteria that are exceeded by one or
more samples include: 2,3,7,8-TCDD, total dioxins, total dioxins and
furans, total hexachloro dioxins, arsenic, beryllium, cadmium,
chromium, lead, and thallium, plus the following radioactive elements:
bismuth-214, cesium-137, potassium-40, lead-212, lead-214, radium-226,
radium-228 and thorium-227.

The purpose of the risk assessments reported in the November document
is to help EPA decide whether the agency needs to regulate cement kiln
dust as a legally hazardous waste or not. Declaring cement kiln dust a
legally hazardous waste would greatly increase the cost of waste
disposal for some cement kilns, and thus might reduce the profitability
of some kilns.

EPA employee Hugh Kaufman has previously charged that the agency has
been "accommodating the regulated cement kiln hazardous waste
incineration industry with nonexistent, or at best loose,

Now that EPA has found dioxins in cement clinker, and dioxins and
radioactive elements in cement kiln dust, the agency will likely come
under considerable pressure to regulate all cement kiln wastes as
hazardous wastes.

For their part, citizens seem likely to start asking themselves anew
whether kilns can be good neighbors.

--Peter Montague


[1] Jeffrey D. Smith, "Cement Kilns 1991," EI DIGEST (August, [1991),]
pgs. 20-32.

[2] Kaufman made his charge in a letter to EPA chief William Reilly
dated Dec. 7, 1990; on February 21, 1991, cement kilns burning
hazardous waste became regulated under the so-called "BIF" (boiler and
industrial furnace) regulations, which can be found in the FEDERAL
REGISTER February 21, 1991, pgs. 7134-[7240.] See also FEDERAL REGISTER
July 17, 1991, pgs. 32688-[32692;] August 27, 1991, pgs. 42504-42517;
September 5, 1991, pgs. 43874-43877; and August 25, 1992, pgs. 38558-

Descriptor terms: cement kilns; hazardous waste incineration; bifs;
sylvia lowrance; cement kiln dust; plutonium; cesium; dioxin;
carcinogens; cancer; lead; chromium; heavy metals; rcra; risk
assessment; edf; concrete;

Error. Page cannot be displayed. Please contact your service provider for more details. (29)