CHEMICAL DATA NOTEBOOK SERIES #73: EPICHLOROHYDRIN
Epichlorohydrin is a flammable, reactive, polymerizable, toxic, irritating, colorless liquid with a pungent odor that resembles garlic. It is used as a curing agent for rubber, a monomer in the polymerization of certain plastics resins, a solvent, and a raw material in the manufacture of lacquers, paints, varnishes, and many other chemicals. It is a suspected human carcinogen.
Epichlorohydrin has a flash point of 87°F, an ignition temperature of 772°F, and a flammable range of from 3.8 to 26.0 percent in air. It has a specific gravity of 1.18, a molecular weight of 92.5, and a vapor density of 3.19. It boils at 239.4°F, freezes at — 71° F, and is only slightly soluble in water. Epichlorohydrin is classified as an epoxide because of the chemical structure resulting from the combination of oxygen in the epoxide “ring” structure with two other atoms, usually carbon. Its molecular formula is CH2OCHCH2Cl.
Epichlorohydrin is classified as a flammable liquid because its flash point of 87°F is below 100°F, the requirement for classification as a flammable liquid. Epichlorohydrin vapors are generated at temperatures below 87°F, but the epichlorohydrin must be raised to a temperature of 87°F before there is a proper ratio of fuel to oxygen in the air for ignition to occur, assuming a proper ignition source is present. In the case of epichlorohydrin, any ignition source capable of causing some small portion of the vapors to reach 772°F (the ignition temperature of epichlorohydrin) will cause the vapors to ignite (and explode), assuming the vapors are within the flammable range.
Once ignited, final combustion products include carbon, carbon monoxide, carbon dioxide, water, and hydrogen chloride. Carbon monoxide is a deadly toxic gas, while hydrogen chloride is an upper respiratory irritant that dissolves in the air’s moisture to form hydrochloric acid.
A very reactive chemical, epichlorohydrin reacts violently and/or explosively with acids, amines, bases, oxidizers, and active metals such as aluminum, magnesium, potassium, sodium, and alloys of these metals and with individual chemicals such as 2aminoethanol, aniline, ethylene diamine, ethyleneimine, iron chloride, isopropylamine, sulfuric acid, and potassium tert-butoxide.
Also a monomer, epichlorohydrin, under the proper conditions, will react with itself to form a long-chain molecule called a polymer. This chemical reaction, called polymerization, is very’ dangerous unless it occurs under the proper conditions inside a proper vessel. When the reaction takes place outside the reactor, the result is an exothermic reaction that releases tremendous amounts of heat energy in such a short time, leading to an explosion. This violent reaction often is referred to as an uncontrolled or “runaway” polymerization. Uncontrolled polymerization can occur anytime epichlorohydrin is subjected to increased heat and/or pressure or when pure epichlorohydrin is contaminated with any chemical with which it reacts. This explosion can resemble a BLEVE (boilingliquid, expanding-vapor explosion) in its power. The polymerization reaction occurring inside a container may increase the pressure so rapidly that the runaway polymerization can indeed produce a BLEVE.
Epichlorohydrin is toxic by ingestion, inhalation, absorption through the skin, and entry’ through a wound. Its TI.V-TWA (threshold limit valuetime weighted average) is being reduced from 2 ppm (parts per million of air) and 7.6 mg/m’ (milligrams per cubic meter) to 0.1 ppm and 0.38 mg/ m3DF
Repeated exposure to vapors above the TLV-TWA may cause problems in the gastrointestinal system; liver pains; and, finally, damage to the kidneys, liver, and lungs. Eye, nose, and respiratory irritation is possible at levels as low as 20 ppm. Exposures of 7,400 ppm for 30 minutes and 250 ppm for four hours have been determined to kill laboratory animals.
If epichlorohydrin contacts the eyes, it will irritate the tissue, possibly causing permanent damage.
When it contacts the skin, epichlorohydrin may produce serious problems, such as blistering, sensitization, and future allergic reactions. The liquid (as well as heavy concentrations of the vapor) absorbed through the skin may cause systemic problems.
Epichlorohydrin is very toxic by ingestion, which will cause convulsions, increased heart action, respiratory paralysis, vomiting, and death. Death can be caused by as little as one gram (35 thousandths of an ounce).
The release of any appreciable quantity of epichlorohydrin should trigger the community’s emergency response plan as mandated by Title III of SARA (Superfund Amendments and
Reauthorization Act of 1986), which will include response by environmental authorities. These environmental experts will be invaluable to the incident commander throughout the incident; they are responsible for offering information on how the environment will be affected by the mitigation techniques the emergency responders choose. In today’s society, the goal of protecting the environment follows closely behind that of protecting human life. The incident commander is responsible for any damage done to the environment through his or her actions and must be able to justify those actions in any inquiry held after the incident has been concluded.
When a hazardous-materials liquid is released, among the first of its properties checked by emergency responders is its flash point. Since epichlorohydrin’s flash point (87°F) is relatively high for a substance classified as a flammable liquid, emergency responders might feel relatively safe in handling the spill —unless, of course, the ambient temperature is at 87°F or above and they believe that the temperature of the epichlorohydrin is also at 87°F or above. The flash point temperature is important because if the liquid’s temperature is below its flash point, not enough vapors will be generated to enter the substance’s flammable range.
Thinking like this is extremely dangerous where epichlorohydrin is involved. Even though its lower flammable limit (3 8 percent in air) may not be reached, more than sufficient vapors will be generated to make it extremely dangerous for anyone without the proper respiratory and skin protection; 3.8 percent concentration in air is 38,000 ppm, well above the 7,400 ppm reported to have killed laboratory animals in four hours. Epichlorohydrin’s toxicity, like that of other toxic materials, is not linear in nature—that is, it probably is not true that if 7,400 ppm will kill an animal in four hours, then 14,800 ppm will kill the same animal in two hours. Death actually could occur in two minutes or within some other specified time. The point is that as the concentration of a toxic gas or vapor in air goes up, the time to death is extremely quicker than one could guess.
Another reason for caution is epichlorohydrin’s reactivity7. In an accidental release, there is no guarantee that the liquid will not come in contact with a material with which it will violently react. The hazard is infinitely greater in a train derailment or other transportation accident, where many other chemicals might be released. Do not overlook the possibility that violent and uncontrolled polymerization might occur. This reaction can occur whether the epichlorohydrin is still in the container or has been released.
With these deadly dangers in mind, carry out all precautions necessary when approaching a flammable liquid: Approach from upwind (not always possible in changing weather conditions), and eliminate all ignition sources immediately. Secure the area immediately surrounding the released liquid and consider evacuation for at least a half mile on all sides; evacuation should be for two miles on the downwind side. Restrict entry into the “hot” zone to emergency responders with proper skin, eye, and respiratory’ protection.
If the container is leaking liquid, it may be possible to catch the liquid and transfer it to a secure container by pump or vacuum. Equipment compatible with the product must be used at all times: Remember that contact with certain metals and their alloys can cause a violent reaction.
If the proper protection and compatible equipment are available, implement procedures for containing the liquids. Build containment dikes around the spill by pushing up walls of sand, soil, or other compatible materials that may be handy, or dig a containment pit and trenches that will lead the spilled liquid to the pit. Environmental authorities must monitor all these actions; consider their advice on the proper containment procedures. These experts must help determine the mitigation procedures that will protect the environment — after the protection of human life is accomplished.
Prevent epichlorohydrin from entering sewers, streams, waterways, or other bodies of water. Any entry into a sewer system may be fatal for all life within the system, but the danger of toxicity and/or explosion will spread throughout the system if it flows into an opening. Alert all sewage treatment facilities immediately.
If epichlorohydrin enters a stream or other body of water, the liquid will sink below the surface as it begins to dissolve. Immediately warn all downstream users of the water. If the stream or river is fast-moving, there may be no way to prevent the contamination from spreading. If, however, there is a large quantity of water moving, the epichlorohydrin will dissolve and rapidly be diluted. Environmental authorities must determine the downstream safety and purity of the water.
If the stream or waterway is slowmoving, it may be possible to dam the waterway so that water movement is diverted to a holding area where the water may be decontaminated. If the volume is low enough, the epichlorohydrin may not fully dissolve and possibly could be pumped out of deep pockets within the waterway. Note that any technique for removing epichlorohydrin from a waterway is extremely difficult. If the water can be contained, carefully mixing activated carbon or peat moss into the water may enable the material to be adsorbed onto the surface; the adsorbent material then can be removed. Since the epichlorohydrin is still present, handle the contaminated adsorbents carefully; they must be disposed of according to federal, state, and local regulations. Any contained water may be aerated by agitation, spraying, or the bubbling of air or other gases through it.
If the epichlorohydrin has entered a pond, lake, or other stationary body of water, you could use the above techniques to remove the product from the contained w ater. Always use compatible equipment.
IDENTIFICATION NUMBERS AND RATINGS
(Chemical Abstract Services)
(Standard Transportation Commodity Code)
(Registry of Toxic Effects of Chemical Substances)
(United Nations/North America)
(Chemical Hazard Response Information System)
(Resource Conservation and Recovery Act)
(U.S. Department of Transportation) flammable liquid
NFPA 704 Rating
(International Maritime Organization)
6.1, poisonous substance
If the epichlorohydrin has been contained on land, the vapors (with a vapor density of 3-19) will move downhill and downwind, “hanging together” for a surprisingly long distance, unless they are broken up by a strong breeze or the action of a highpressure water spray or fog. If water is used to disperse the vapors, contain the runoff water. Applying alcoholtype foam may slow the production of vapors, as w ill covering the material in a containment pit with sheets of compatible material.
These moving vapors may collect in enclosed and/or low-lying areas and be a serious hazard to anyone who might enter without the proper protection. Flowing flammable vapors always seem to keep moving until they find an ignition source and then flash back to the source of the vapors.
The dilution technique also may be used, keeping in mind that the epichlorohydrin dissolves in water only at a rate of 6.6 percent by weight (higher if the water is cold). Also remember that this technique is recommended only if the resulting epichlorohydrin solution can be contained.
If contained, the relatively pure material, or a resulting solution, can be removed by a salvage firm or the manufacturer, buyer, or shipper of the product. Both will provide properly educated, trained, protected, and equipped employees. Any remaining liquid can be absorbed by using common absorbents such as cement powder, clay, fly ash, sand, sawdust, soil, or other available compatible absorbing agents, including commercial absorbents. Firefighters should not become involved in cleanup or salvage techniques unless human life is threatened.
If a container of epichlorohydrin is heated by the radiated heat of a fire or by impinging flames, the pressurerelief device, usually a spring-loaded valve, will operate, allowing vapors to escape and the pressure within the container to be relieved. If the escaping vapors are burning, do not extinguish them. If they are extinguished, the vapors will build up to a dangerously high level before being ignited explosively. Containers exposed to such energy input should be cooled by applying water with unmanned appliances from as far away as possible. The danger of a BLEVE is present whenever a container of liquid or gas is exposed to energy that might cause internal pressure to rise faster than the container’s pressure relief devices can handle.
alpha-epichlorohydrin 1 -chlor-2,3-epoxypropane
1 -chloro-2,3-epoxypropane 3-chloro-1,2-epoxypropane (chloromethyl) ethylene oxide
2-(chloromethyl) oxirane chloropropylene oxide
3-chloro-1,2-propylene oxide chloromethyloxirane
2 -chloromethyloxirane chloro-1,2-propylene oxide 2-chloropropylene oxide (dl)-alpha-epichlorohydrin ECH
2.3-epoxypropyl chloride gamma-chloropropylene oxide glycerin epichlorohydrin glycidyl chloride
If epichlorohydrin’s burning escaping vapors are extinguished, they may need to be deliberately ignited beforeenough of them can collect to cause a disastrous explosion.
Never allow yourself to get caught between a fire and containers of any combustible or flammable liquid or compressed gas. The energy radiated from the fire can cause the container to vent its contents, ignite, or explode or create any combination of these unwanted events.
A small pool of epichlorohydrin may be extinguished (depending on weather conditions) by applying alcohol-type foam, carbon dioxide, dry chemical, or water spray or fog. The relatively low ignition temperature of 772°F means that any common ignition source can produce sufficient energy to cause some small part of the vapors to reach this temperature, producing ignition, sometimes explosively. The low ignition temperature also means that if any metal part has been exposed to the fire, it easily could be raised above that temperature—a previously extinguished fire, therefore, can be ignited by the hot metal and explode back to life again.
If the fire is in a locale where human life, the environment, property, and societal systems are not threatened, it might be best to allow the fuel to burn itself out. When the combustion products of epichlorohydrin pose no danger, allowing the fuel to burn itself out may be the most desired technique.
After the fire has been extinguished, emergency responders should not be involved in cleanup or salvage. Containers still holding product may have been so weakened that any movement might precipitate another spill. Firefighters should stand by as professional cleanup teams, guided by the environmental authorities, move in. Environmental experts must supervise the final cleanup; they will determine when the land and waterway are safe.
PROTECTIVE CLOTHING AND EQUIPMENT
The protective clothing and equipment chosen must prevent the epichlorohydrin from contacting the eyes or skin. Rubber gloves, aprons, and boots may offer some skin protection; splashproof chemical goggles are needed to protect the eyes. Positivepressure, self-contained breathing apparatus (SCBA) must be used for respiratory protection. Manufacturers of total encapsulating suits claim that suits made of butyl rubber and VitonTM offer protection for some period of time. Contact the individual manufacturers of these suits for the degree of safety offered by each recommended material; also consult the manufacturers of epichlorohydrin for their recommendations.
Inhalation. Move the victim to fresh air; keep him/her calm and warm. If the victim’s breathing has stopped or becomes labored, administer artificial respiration, being aware that such action might expose the first-aid giver to the material in the victim’s lungs and/or vomit. Immediate medical attention is needed.
Eye contact. Flush the eyes immediately for at least 15 minutes, lifting the eyelids occasionally. Immediate medical attention is needed.
Skin contact. Wash the affected areas with large amounts of soap and water. If irritation continues after washing, medical attention is needed.
Ingestion. If the victim is conscious, make him/her drink large quantities of water or milk immediately, and induce vomiting. One reference warns that vomiting should not be induced if immediate medical attention is available. Never try to make an unconscious person drink anything or try to make him/her vomit. Immediate medical attention is needed.