Books and Publications
Publications from the
World Health Organization
Selected Chloroalkyl Ethers,
Environmental Health Criteria, No. 201
This book evaluates the risks to human health and the environment posed
by exposure to bis(2-chloroethyl) ether (BCEE), bis(chloromethyl) ether (BCME),
and chloromethyl methyl ether (CMME). These three ethers, which are part of
the large class of chloroalkyl ethers, are used as solvents and in several
industrial processes, including the manufacture of polymers. BCEE is also
used in the textile industry, as an intermediate in the manufacture of pharmaceuticals
and other chemicals, and as a soil fumigant, insecticide, and acaricide. While
data on risks to the environment are limited, the report draws on a considerable
body of evidence, from laboratory animals and epidemiological studies of exposed
workers, indicating that BCME and CMME are potent human carcinogens.
A section on sources of these chemicals in the environment notes that BCEE
may enter the environment as a by-product from the chlorination of waste streams
containing ethylene or propylene, and as a contaminant in the fungicide metam-sodium.
BCME and CMME are released, in small amounts, from industrial activities.
Concerning environmental behavior, the report concludes that BCEE is rapidly
volatilized from surface water, does not adsorb to soil or sediment, and may
reach groundwater. The chemical may be persistent due to the relative stability
of b-chloroalkyl ethers. The report found no evidence that BCEE bioaccumulates
or biomagnifies to any significant extent. For BCME and CMME, evidence pointing
to extremely short residence times supports the conclusion that levels in
the environment are extremely low, if not nonexistent.
A section on sources of human exposure draws on limited data indicating that
occupational exposure to BCEE may occur, via inhalation or dermal contact,
in the dry cleaning and textile industries or during the processing of gum,
lacquer, oil, paint, soap, and tar. For BCME and CMME, data suggest that occupational
exposure may occur in laboratory and textile workers, and during the production
of anion-exchange resins, selected organic chemicals, and polymers. In occupational
settings where vapors of formaldehyde and hydrochloric acid coexist, BCME
may form spontaneously in air. The report also found evidence that the general
population may be exposed to BCME and CMME through the use of mosquito coils.
The most extensive section evaluates the large number of studies, in laboratory
animals and in vitro test systems, conducted to assess toxic effects.
BCEE is noted to be acutely toxic by the oral, inhalation, and dermal routes.
Exposure via inhalation to high concentrations resulted in eye irritation
and congestion, edema, and hemorrhage in the lungs. Inhalation of BCME resulted
in irritation of the eyes and respiratory tract, and necrotizing bronchitis.
Exposure to CMME produced similar effects. In vitro testing for mutagenicity
produced positive results for all three chemicals. In carcinogenicity studies,
animals exposed to BCME showed a significantly elevated incidence of pulmonary
adenomas and respiratory tumors. Studies of CMME toxicity have shown increased
incidence of tracheal metaplasia and bronchial hyperplasia in a dose-dependent
The evaluation of effects on human health concentrates on evidence of an
increased risk of lung cancer demonstrated in eight epidemiological studies
of workers exposed to BCME and CMME. In all of these studies, the type of
lung cancer, the standardized mortality ratios, the latency periods, and average
age when lung cancer appeared were remarkably consistent. Moreover, the report
notes that the type and incidence of lung cancer, seen in relatively young
individuals after latency periods as short as two years, are distinct from
those caused by tobacco. On the basis of this evidence, the report recommends
that exposure to BCME and CMME should be eliminated.
Selected Chloroalkyl Ethers, Environmental Health Criteria, No. 201,
1998, xviii + 95 pages (English with summaries in French and Spanish), ISBN
92 4 157201 9, CHF 26.-/USD 23.40; In developing countries: CHF 18.20, Order
no. 1160201. WHO distribution and sales, CH-1211 Geneva 27, Switzerland.