CHEMICAL DATA NOTEBOOK SERIES #66: ANILINE
HAZARDOUS MATERIALS
Aniline is a toxic, combustible, reactive, corrosive, irritating, colorlessto-brown liquid with a musty, fishy odor. Used in the manufacture of agricultural chemicals, dyes, explosives, fibers, fungicides, herbicides, inks, perfumes, petroleum-refining chemicals, pharmaceuticals, photographic chemicals, rubber chemicals, sweetening agents, varnishes, and many other chemicals, aniline is one of the most important chemicals in commerce today. Its molecular formula is C(sometimes written CN).
PROPERTIES
Aniline has a flash point of 158°F, an ignition temperature of 1,139°F, and a flammable range of from 1.3 to 11.0 percent (one reference gives the upper flammable limit as being “from 20 to 25 percent”) in air. It has a specificgravity of 1.024, a molecular weight of 93, and a vapor density of 3 21. Its boiling point is 363.6°F. It freezes at 20.7°F and is slightly soluble in water.
HAZARDS
Aniline’s primary hazard is toxicity. The lethal dose for a person of average size is only 10 grams. Serious poisoning symptoms will result from ingesting only 0.25 ml (milliliters, or thousandths of a liter), or about 0.007 ounce. Its TLV-TWA (threshold limit value-time weighted average) is 2 ppm (parts per million of air), its STEL (short-term exposure limit ) is 5 ppm (for 15 minutes), and its IDLH (immediately dangerous to life and health) is 100 ppm. The average person can detect it by smell at a level around 0.1 ppm.
Established maximum levels of exposure are very important to employees of companies that use, store, or transport hazardous chemicals, especially those that have a toxicity level as high as aniline’s. They inform management and all potentially exposed employees of the maximum level of exposure possible without harming employees. Employees then can wear the proper protective clothing and equipment to protect themselves when the maximum safe levels of concentration are surpassed.
No such protection, however, is offered to emergency responders. An accidental release of almost any quantity will expose the responders to quantities far above the maximum allowed without respiratory, eye, or skin protection. The consequences of such acute exposures are very serious: An exposed person can die before the real danger is realized. Emergency responders should not disregard maximums imposed by the government simply because the maximums were not designed specifically for them. Responders should realize that they may be subjected to exposures hundreds or thousands of times more dangerous than company employees will, and they should protect themselves accordingly.
Aniline reacts with the hemoglobin in the red blood cells in the human body and forms mcthcmeglobin. As the methemeglobin forms, the red blood cell no longer is able to pick up oxygen in the lungs to carry to the body’s cells, and it cannot remove waste C0 from the cells. The result is cyanosis, a bluish or purplish discoloration of the skin common to this type of poisoning and caused by deficient oxygenation of the blood. Additional symptoms, sometimes delayed for up to four hours, may include confusion, disorientation, drowsiness, mouth dryness, lack of muscle coordination, lethargy, nausea, ringing in the ears, shortness of breath, vertigo, and weakness. These symptoms can be initiated by levels as low as 7 ppm. Unconsciousness, coma, and death may follow if medical treatment is delayed after exposure to toxic levels.
Chronic aniline exposure —which is a hazard for workers in industries where aniline is a common raw material-can cause anemia, anorexia, skin lesions, and weight loss. The regulations against exposure at levels above the TLV-TWA and STEL do not mean that workers cannot be in an atmosphere where the concentrations of aniline in the air are above these maximums. They simply mean that when concentrations of the regulated chemical are above the established maximums, anyone working in this atmosphere must have the proper respiratory, eye, and skin protection. Injuries caused by exposure to chemicals occur where (a) workers refuse to wear the proper equipment and/or clothing; (b) a malfunction in process equipment allows the chemical to be released in amounts that permit it to accumulate in quantities above the established maximums; (c) management does not properly monitor the work atmosphere; or (d) management does not provide the proper protective clothing and equipment, or if it does, it does not enforce regulations concerning their use.
There is no excuse for employees of companies using, storing, or distributing hazardous chemicals to suffer chemical injuries. Even accidental releases in the workplace are preventable, as are all other types of accidents. And even if some accidental releases should occur, the protective equipment and clothing provided should prevent injuries and illnesses.
Accidental releases of hazardous chemicals outside the place of use or storage or in transportation accidents can cause serious injuries to bystanders, occupants near the release, and emergency responders who are not properly protected. It is not possible to protect the first three groups with proper protective clothing and equipment, but emergency responders should not get involved in mitigating the incident until they are properly protected. Proper protection implies not only the proper protective clothing and equipment but also the proper education and training. This is mandatory for most haz-mat responses but is particularly important in the case of aniline releases.
Aniline is also combustible. Often when extreme toxicity is the primary hazard of a chemical, as is the case with aniline, additional hazards such as combustibility and reactivity can be overlooked. Aniline, however, will burn, and when it burns, it liberates in addition to carbon monoxide carbon dioxide, carbon, water, and the family of toxic gases known as the nitrogen oxides, usually designated with a shorthand notation of NO This group of toxic gases includes nitrous oxide (N), which is not particularly toxic; nitrogen oxide (NO); nitrogen trioxide, also known as nitrogen sesquioxide (N; nitrogen peroxide, also known as dinitrogen tetroxide ; nitrogen dioxide (N0 dinitrogen pentoxide and trinitrogen tetroxide Many of these combustion products are carried away by the thermal column and do not endanger anyone. Anyone without respiratory protection in close proximity to the fire will be exposed to them, however, and may inhale enough of the nitrogen oxides to cause lung damage. Nitrogen-oxide poisoning is insidious in that the effects may be delayed from six to 48 hours. At that time, the victim becomes short of breath, begins to perspire, and experiences chest pain that intensifies and spreads down the left arm within a short period of time. Breathing becomes impossible, and the victim collapses and dies. When this occurs to an overweight, out-ofshape firefighter, officer, or chief officer, the diagnosis is heart attack, and usually no autopsy is performed.
The relatively high flash point of 158°F means that aniline must be heated to this temperature before it begins to liberate vapors sufficient to form an ignitable mixture with the air near the surface of the liquid or the container. This property may lull emergency responders into thinking that the material is relatively safe from burning. Even its ignition temperature of 1,139°F seems relatively safe, even though this temperature easily is reached by most common ignition sources. Its flammable range of from 1.3 to 11.0 percent in air (or 20 to 25 percent) indicates that it can enter the proper ratio with air rather quickly and almost never may become too rich to ignite. Emergency responders must realize that a toxic substance like aniline will ignite and burn, many times with explosive and otherwise dangerous effects.
Aniline reacts violently with many substances, including acetic anhydride, boron trichloride, chlorosulfonic acid, dibenzoyl peroxide (benzoyl peroxide), diisopropyl peroxydicarbonate, fluorine, fluorine nitrate, hydrogen peroxide, nitromethane, nitrosyl perchlorate, oleum, ozone, perchloric acid, perchloryl fluoride, peroxodisulfuric acid, peroxomonosulfuric acid, peroxyformic acid, potassium peroxide, red fuming nitric acid (RFNA), silver perchlorate, sodium peroxide, sulfuric acid, tetranitromethane, toluene diisocyanate, and other diisocyanates, perchromates, strong acids, and strong oxidizers.
Aniline is corrosive to many metals, some plastics, and some rubber compounds. It is irritating to human skin, which absorbs it rapidly. Aniline is a severe eye irritant and may cause permanent corneal damage.
NONFIRE RELEASE
Any accidental release of aniline should trigger the community’s emergency response plan. All available medical personnel must stand by to treat poison victims on an emergency basis. Environmental authorities must be present to determine the spread of the aniline in the environment; after monitoring the potential harm to humans, they should be available to advise the incident commander on actions that will lessen the potential damage to the environment.
Any accidental release of aniline necessitates all precautions that must be taken for the release of any deadly poison. Evacuating all humans from an area of at least one mile around the release must be the first action taken. Downwind, consider evacuation for at least another mile. For a very large spill such as one that might occur in a tank-wagon or rail-car incident, consider even w ider areas of evacuation, especially downwind. No one should be allowed to enter the “hot” zone around the spill without proper respiratory, eye, and skin protection.
Aniline’s vapor density of 3 21 means that its vapors are considerably (3 21 times) heavier than air. As they leave the scene of the release, these vapors sink to the ground and flow along low spots in the terrain. They “hang” together for long distances unless disturbed by the wind. Any blowing wind spreads the vapors further, and any wind change widens the danger area. Rapid action must be taken to save lives, since it does not require much aniline to produce serious harm, including death, to humans. Aniline’s vapors accumulate in low spots or enclosed areas, and anyone entering such an area quickly can be overcome. Although the threat of the vapors igniting and causing an explosion is serious enough, the vapors’ toxicity is a larger threat. Aniline is not a very volatile material, so vapors will not be generated as fast as flammable liquids; the danger from vapors nevertheless must be anticipated because of the toxicity of the material.
Standard procedures for containing a released liquid, such as constructing a containment pond by using pushedup soil or sand to form dikes, may be employed. A containment pit, with dug trenches that lead the spilled liquid to the pit, may be used. Compatible tools and equipment must be used.
Anyone attempting to stop a leak of the material must have the proper protection, and any materials used to plug a leak should be compatible with the material. Vapors from a l or a leak under pressure can be dispersed by the sweeping action of a highpressure spray or water fog. The runoff water will have to be contained.
Professionals—never firefighters or other emergency responders—should salvage the spilled aniline. The emergency response plan will have prompted notification of the shipper, the manufacturer, and the buyer. It is the responsibility of one or more of these companies to perform salvage and cleanup activities or to arrange to have professionals do it. The material may be suctioned into secure containers and removed. Any remaining liquid can be absorbed by the use of soil, sand, peat moss, fly ash, cement powder, or any other commercial sorbent. The environmental authorities will monitor the cleanup and decide when the environment is free of contamination.
Aniline, or any other hazardous material, must not be allowed to enter a waterway or sewer system. Catch basins and manholes should be diked or dammed. Should aniline enter a sewer, notify all sewage-treatment facilities immediately and give the proper name of the chemical and all of its hazards, particularly details about its toxicity. Consult the manufacturer of the aniline for the best way to handle the aniline once it has entered the sewer system. Entry certainly will kill all rats and other unsavory occupants of the sewers, but the safety of people throughout the community must be of primary’ concern.
IDENTIFICATION NUMBERS AND RATINGS
CAS
(Chemical Abstract Services)
62-53-3
STCC
(Standard Transportation Commodity Code)
4921410, pure material 4921492, aniline sludge for furnace use
RTECS
(Registry of Toxic Effects of Chemical Substances) BW6650000
UN/NA
(United Nations/North America)
1547
CHRIS
(Chemical Hazard Response Information System) ANL
RCRA
(Resource Conservation and Recovery Act)
U012
DOT
(U.S. Department of Transportation)
Poison B
NFPA 704 Rating
3-2-0
IMO
(International Maritime Organization)
6.1 poisonous substance
If the released aniline enters a waterway, notify all downstream users of the w ater at once. As aniline contacts water, it slowly begins to dissolve as it sinks below the surface. In a pond or lake, the aniline flows to the lowest part as it dissolves slowly. In a river or stream, the aniline, again, sinks to the bottom as it slowly dissolves, but it also moves with the water downstream, traveling along the stream bed. The rate at which aniline dissolves in the water depends on the volume of the w ater and the speed at which it is moving. The faster the water moves, the faster the aniline dissolves and spreads throughout the water. The environmental authorities constantly monitor the water to determine the rate and amount of contamination occurring.
A professional salvage crew may suction the undissolved aniline off the bottom of a lake or pond, if the crew’ is brought to the scene in time. Chances are, however, that the entire amount of aniline entering the water will completely dissolve. This also is true in the case of moving w ater. Building a dam to contain the spilled liquid below the surface of the water works only if a nonsoluble liquid is involved. Since the aniline eventually dissolves totally in the moving water, the only hope for containing the contamination is to stop the flow of water completely with a huge dam (this might not be practical or possible) or to divert the flow of the contaminated water into a low-lying area where all the water may be impounded. Once the water is contained, the manufacturer of the aniline should be contacted and asked to decontaminate it. Again, the environmental experts will determine when the water is safe for release and subsequent use.
Decontamination of the water may be accomplished by aeration, air stripping, or sparging. These techniques, however, will cause a release of aniline vapors into the air, which could be extremely dangerous and usually are not recommended for materials with aniline’s toxic properties.
In some cases, adding activated carbon causes the adsorption of the aniline onto the carbon; the aniline subsequently can be recovered. The contaminated carbon must be handled as a hazardous material, since it will be holding the toxic aniline on its surface. Adsorption techniques must be carried out only by qualified experts, and the contaminated carbon must be disposed of according to federal, state, and local regulations.
FIRE SCENARIO
All containers of aniline, like any other combustible (or flammable) liquid, should not be subjected to the increased heat of a fire, whether that heat is from impinging flames or radiated heat. All containers subjected to heat sources should be cooled by applying water w ith unmanned appliances from as far away as possible. Any sudden release of hot aniline caused by the failure of the container due to increases in internal pressure evolves tremendous amounts of toxicvapors into the air in concentrations that quickly become lethal to anyone without proper protection. If failure of a container is imminent, immediately withdraw all personnel. Emergency responders must be aware from the beginning that toxicity is the primary hazard and that mass poisoning of anyone exposed is a veryreal possibility, even if the exposure is thought to be minor.
Burning aniline may be extinguished by carbon dioxide, dry chemical, foam, or water. However, if vapors escaping from a container are burning, the flames should not be extinguished until the flow of vapors can be stopped immediately after extinguishment. Aniline, in fact, is so toxic that it might be decided to allow all of the product to be consumed in the flames while protecting people from the toxic products of combustion and protecting exposures from the spread of the fire.
In some extreme cases where the aniline has not been ignited but the danger of the toxic vapors is so great as to threaten lives, deliberately igniting the aniline may be the option chosen. Deliberate ignition always should be considered as a last resort in cases where the fire and toxic combustion products represent a considerably lesser threat than mass poisoning and all other mitigation techniques have proved ineffective.
Other than considering the enormous threat posed by toxicity, fires involving containers of aniline should be handled like all other fires involving containers of combustible liquids.
PROTECTIVE CLOTHING AND EQUIPMENT
Protective clothing and equipment must prevent any contact of the aniline with the eyes or skin. Rubber gloves, aprons, and boots may offer some skin protection, while splashproof chemical goggles should be worn to protect the eyes. Positivepressure. self-contained breathing apparatus must be used for respiratory protection. Manufacturers of total encapsulating suits claim that suits made of butyl rubber, chlorinated polyethylene, natural rubber, neoprene, nitrile rubber, polyethylene, polyvinyl alcohol, styrene-butadiene rubber, and Viton offer protection for some period of time. Contact the manufacturer to determine the degree of safety offered by each recommended material as well as the manufacturers of aniline for their recommendations.
FIRST AID
Inhalation. The victim should be moved to fresh air and kept calm and warm. If the victim’s breathing has stopped or become labored, administer artificial respiration. First-aid givers should be aware that they could be exposed to the material in the victim’s lungs and/or vomit. Immediate medical attention is needed.
Eye contact. Flush eyes immediately for at least 15 minutes, lifting the eyelids occasionally. Immediate medical attention is needed.
Skin contact. Wash the affected areas of the body with large amounts of soap and water. Since aniline will be absorbed through the skin, wash all aretes of the body, including hair, fingernails, toenails, nostrils, and ears (interior and exterior). Immediate medical attention is needed.
SYNONYMS
arninobenzene aii~ inophen anilin aniline oil Anzvin Blue oil benzeneamine C.I. 76000 Kyanol NCI-c03736 phenylarnine
Ingestion. A conscious victim should be made to drink large quantities of water immediately; induce vomiting. Never give an unconscious person anything to drink and do not induce vomiting. Immediate medical attention is needed.*
