Chloroform is an interesting chemical. It’s famous for its ability to act as an anesthetic and is useful in industry and science laboratories. It’s a toxic substance, however, and can cause serious health problems. These include organ damage and heartbeat irregularities. At high concentrations, inhalation of chloroform can depress the respiratory system so much that death occurs. The chemical is also strongly suspected of increasing the risk of cancer.
Chloroform is widespread in the environment and is made both naturally and artificially. Most people are exposed to low levels of the chemical, but some people—especially those working in certain industries—are exposed to higher levels. Fortunately, there are ways in which we can limit our exposure to chloroform.
Chloroform is also called trichloromethane and has the formula CHCl3. At room temperature, it’s a clear, colorless, and dense liquid that has a pleasant odor and is nonflammable. It tastes sweet but produces a hot, burning sensation in the mouth and throat. Contact with the liquid produces sores on the skin. The liquid form of chloroform is a volatile substance. This means that it has the tendency to change into a vapor at normal environmental temperatures.
Chloroform is made synthetically for industrial use and is produced naturally from chlorine in the environment. It’s also made by some seaweeds and microalgae. Its non-medical applications are useful, but the chemical needs to treated with care when it’s used in laboratories and industrial processes.
Chloroform was discovered in 1831 and 1832 by three different scientists working independently—an American doctor named Samuel Guthrie, a French chemist named Eugene Soubeiran, and a German chemist called Justus von Liebig.
A few years after its discovery, scientists realized that chloroform could act as an anesthetic. It causes a person to lose consciousness because it depresses central nervous system activity. The central nervous system consists of the brain and the spinal cord.
James Young Simpson, a Scottish obstetrician and surgeon, popularized the use of chloroform as an anesthetic. He discovered the chemical’s abilities from personal experience. In 1847, Simpson and some friends deliberately inhaled chloroform to explore its effects. They were all rendered unconscious, but luckily they didn’t inhale enough vapor to kill themselves. The experiment was potentially dangerous. Simpson was very impressed by the results of his investigation.
Chloroform quickly replaced ether as the anesthetic of choice, since unlike ether it didn’t have a strong and unpleasant smell, could be used in smaller quantities, started to work more quickly, and wasn’t flammable.
Chloroform gained prominence when it was administered to Queen Victoria in 1853 during the birth of Prince Leopold, her eighth child. She also inhaled the chemical in 1857 during the birth of Princess Beatrice, her ninth and final child. The administrator of the drug was Dr. John Snow. He used enough chloroform to relax his patients during childbirth but not enough to render them unconscious. This required a very careful calculation of dose.
Chloroform was found to be very effective as an anesthetic. However, one serious problem with its use in medicine is that it has a low margin of safety. This means that there is only a small difference between a dose that is helpful and a dose that is harmful. In addition, chloroform inhalation for the purpose of anesthesia produces a number of potentially dangerous side effects.
Today scientists know that chloroform is not the wonder chemical that it first appeared to be. When it’s inhaled, it can cause heartbeat irregularities that may be deadly. It can also cause liver and kidney damage. High concentrations of the chemical may produce headaches, dizziness, and gastrointestinal problems such as nausea and vomiting. In addition, chloroform has been classified as a probable carcinogen—a chemical that can cause cancer. Newer anesthetics have replaced chloroform in the operating room.
Chloroform is rapidly absorbed through both the respiratory tract and the gastrointestinal tract. It can also be absorbed through the skin. Once inside the body, it travels widely. Most of the chemical is eventually broken down or leaves the body by exhalation and excretion, but some may collect in body fat and organs.
Chloroform can be dangerous without being absorbed. Ultraviolet radiation from sunlight causes chloroform and oxygen in the environment to slowly react, forming a gas called phosgene. This gas is more toxic than chloroform and is especially dangerous if it collects in an enclosed space and becomes concentrated. Phosgene was used as a chemical weapon in World War One.
Interestingly, phosgene is an important industrial chemical today. Great care has to be taken when using it, however. It’s a strong irritant in both its gaseous and its liquid form. It damages tissues in the nose, throat, and lungs and causes choking. It also irritates the skin and eyes.
Research has shown that the biggest contributor to chloroform in our bodies is chlorinated water. Chlorine is often added to drinking water and swimming pool water to kill bacteria and other microbes. This job is very important, but unfortunately using chlorine as a disinfectant can cause problems.
Chloroform and other disinfection by-products form when chlorine reacts with organic molecules in water. In swimming pools, these organic molecules can come from shed skin cells, sweat, urine, cosmetics, sunscreens, leaves, and soil, for example. Once they are formed, chloroform and the other disinfection by-products are absorbed though the skin or enter the body when a person swallows water or breathes vapor coming from the water.
Scientists have found that chlorinated water in homes produces vapor containing chloroform, especially if the water is hot. The hotter the water, the higher the concentration of the chemical in the air. Hot shower or bathwater, hot cooking water, and hot laundry or dish washing water can all increase the concentration of chloroform in a home. Chlorine used to clean toilets or to bleach clothes can have the same effect.
Certain industries release chloroform into the atmosphere. They use the chemical as a reactant in chemical reactions and as a solvent—a chemical that dissolves other substances. Chloroform is used in some countries to produce a refrigerant known as R-22. The use of R-22 is gradually decreasing, however, since it causes ozone depletion in the atmosphere. Chloroform is also released into the air from pulp and paper mills and from landfills and hazardous waste sites.
Chloroform enters our bodies when we drink chlorinated water and eat food containing the chemical. The chemical is present in some foods because chlorinated tap water was used to produce them.
The effects of chloroform on our bodies depend on the concentration of the chemical and the length of time that we are exposed to it. There are several steps that we can take to reduce the absorption of the chemical. The last step in the list below may require the help of officials.
- Use water and shower filters that reduce the chlorine level in home water.
- Take shorter showers and baths.
- Use less hot water in the home.
- Open windows to improve ventilation in areas where chloroform is likely to form.
- Avoid the use of cleaning products that contain chlorine.
- Use other swimming pool disinfection methods instead of chlorine. This step is especially important for someone who is a frequent swimmer in a pool.
Most of us don’t need to worry excessively about the amount of chloroform that we absorb. It is a good idea to be aware of the potential dangers, however, and to reduce the intake of the chemical whenever possible. People working in jobs where chloroform is made or used or those living near a facility that releases it into the environment need to be careful. The risk of ill effects is highest for these people.
Chloroform facts and public health information from the Agency for Toxic Substances and Disease Registry
Information about chloroform from the New Jersey Department of Health
Chloroform formation and hazards from the EPA (Environmental Protection Agency)
Facts about Sir James Young Simpson from the Gazetteer for Scotland
Phosgene facts from the CDC (Centers for Disease Control and Prevention)