Health effects of bis(chloromethyl) ether
Contents
Introduction
Bis(chloromethyl) ether (BCME) is a man-made chemical with a strong, unpleasant odor. It is a clear liquid at room temperature, but it readily evaporates into air. BCME undergoes chemical reactions easily, so it is broken down very rapidly when it comes into contact with water. Consequently, any BCME that might escape from a chemical plant or a chemical waste site into water or moist soil would be destroyed within a few minutes. BCME that escapes into air is also broken down by reacting with water and other chemicals, but this takes a few hours. BCME was used in the past to make several types of polymers, resins and textiles. However, because BCME is believed to cause cancer in humans, these uses have been stopped. BCME is now used only in small amounts inside fully enclosed systems in chemical plants. (Health effects of bis(chloromethyl) ether)
Exposure to BCME
Since BCME has such limited use in the United States, chances for exposure to BCME are low. Some BCME can form as an impurity during the production of other chemicals, so exposure might occur in chemical plants that make or use these chemicals. Also, some BCME may exist in chemical waste sites, although this is not certain. Because BCME evaporates easily, the most likely way to be exposed to BCME in the workplace or around a waste site is by breathing air containing BCME vapors. However, information on levels of BCME which exist in air is not available.
Pathways for BCME in the body
Because BCME is so quickly broken down by water, most BCME that contacts the body is quickly changed into other chemicals (formaldehyde and hydrochloric acid) before it passes through the outermost layer of cells contacted (e.g., the cells that line the nose, windpipe and lungs). Some BCME may enter into the blood or internal tissues, but this has not been studied and the amount may be too small to measure.
Health effects of BCME
You should know that one way to learn whether a chemical will harm people is to determine how the body absorbs, uses, and releases the chemical. For some chemicals, animal testing may be necessary. Animal testing may also help identify such health effects as cancer or birth defects. Without laboratory animals, scientists would lose a basic method for getting information needed to make wise decisions that protect public health. Scientists have the responsibility to treat research animals with care and compassion. Scientists must comply with strict animal care guidelines because laws today protect the welfare of research animals.
Additionally, there are vigorous national and international efforts to develop alternatives to animal testing. The efforts focus on both in vitro and in silico approaches and methods. For example, the National Toxicology Program (NTP) at the National Institute of Environmental Health Sciences (NIEHS) created the NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) in 1998. The role of NICEATM is to serve the needs of high quality, credible science by facilitating development and validation—and regulatory and public acceptance—of innovative, revised test methods that reduce, refine, and replace the use of animals in testing while strengthening protection of human health, animal health and welfare, and the environment. In Europe, similar efforts at developing alternatives to animal based testing are taking place under the aegis of the European Centre for the Validation of Alternative Methods (ECVAM).
Studies of people exposed to BCME in the workplace show that breathing of BCME vapors causes irritation to the nose, throat, and lungs. Contact with the liquid is also highly irritating to skin. In animals, breathing in high levels of BCME causes swelling and bleeding in the lung and can cause death. Workers exposed to BCME have been shown to have a higher-than-expected incidence of lung cancer. This observation is supported by studies in animals which also show that BCME can cause cancer.
Harmful levels of exposure to BCME
No information exists for either animals or humans on harmful health effects following oral exposure, but oral exposure is of little concern since BCME breaks down in water or moist foods and exposure is not likely by this route. Direct skin contact with even small amounts (less than a drop) of the liquid form of BCME causes severe skin irritation at the site of contact. It is not known what levels result in health effects in people from breathing BCME. In animals, lung injury has occurred from short and long-term exposure to levels of 0.7 parts per million (ppm) BCME and greater. An increased number of deaths due to nasal tumors was seen in animals exposed to BCME in air at levels of 0.1 ppm for 6 months.
Medical tests for exposure to BCME
Because BCME is broken down so rapidly in the body, there are no specific tests to determine if a human has been exposed to this compound. The only available medical tests are physical examination of the nose and throat, chest X-ray, and examination of the sputum for abnormal cell types. Unfortunately, these tests are not specific for this compound, and would reveal effects of the compound only after damage to the tissues had already occurred.
Further Reading
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