CHEMICAL DATA NOTEBOOK SERIES #65: TRIMETHYLAMINE
HAZARDOUS MATERIALS
Trimethylamine is a flammable, toxic, irritating, colorless gas with a pungent odor described as fishy, ammonia-like, or both. Used in disinfectants, flotation agents, insect attractants, and plastics, it also is a raw material used to manufacture many other chemicals. It may be shipped as liquefied gas or as a solution of the gas in water.
PROPERTIES
Trimethylamine is a gas, and gases have no flash points. However, trimethylamine often is shipped as a water solution. The flash point cited for a solution of 25 percent trimethylamine in water is 10°F. It has the following properties: a flammable range of 2.0 to 11.6 percent in air, an ignition temperature of 374°F, a specific gravity of 0.632, a molecular weight of 59, and a vapor density of 2.03 It boils at 24.8°F, freezes at – 179°F, and is soluble in water. Its molecular formula is (CH.O3N.
HAZARDS
A flammable gas with an extremely low boiling point, trimethylamine generates flammable gases at all ambient temperatures where it is transported, stored, or used. Its ignition temperature of 374°F is extremely low, and the gas can be ignited by many other ignition sources besides flames and sparks. Hot metal, superheated liquids (liquids heated under pressure), or radiant heat from another source would be sufficient to raise the temperature of the material to its relatively low ignition temperature, causing an explosion when the gas ignites.
Its flammable range of from 2.0 to 11.6 percent in air starts at a relatively low lower flammable limit and has a range of almost 10 percent. Indications are that trimethylamine will get into its flammable range very quickly and, outdoors at least, most probably will not be “too rich” to burn.
The high vapor density of trimethylamine means that its vapors will hang together and flow along low spots in the terrain unless they are disturbed by winds. The vapors will flow (gases and vapors are fluids, like liquids) until they find an ignition source, at which point they will ignite explosively and “flash back” to the vapor source. Vapors that accumulate in low spots or confined areas will become a serious (if not deadly) trap for anyone wandering into the vapors without respiratory protection or entering carrying an ignition source.
Anhydrous liquefied gas produces the greatest amount of flammable vapors, but the gas in water solution can really surprise those who believe that the solution is harmless since the gas readily dissolves in water. On the contrary, the 25 percent solution of trimethylamine in water, the usual concentration for shipment, is itself classified as a flammable liquid, having a flash point of 10°F. This makes this solution as deadly as many common hydrocarbon solvents with flash points within 10°F or 20°F of the 25 percent trimethylamine solution. And since the technique of diluting with water is effective for mitigating a trimethylamine release, emergency responders might overlook the hazards inherent in the commercial solution.
Trimethylamine is toxic, with a TLV-TWA (threshold limit value-time weighted average) of 10 ppm (parts per million in air) and an STEL (shortterm exposure limit) of 15 ppm. Levels of trimethylamine inhaled below 100 ppm can irritate the eyes and respiratory system. More serious respiratory and eye problems occur above 100 ppm; chemical pneumonitis and pulmonary edema are real possibilities. Delayed reactions may occur, and progressively higher concentrations can cause lung problems severe enough to cause death.
Contact of trimethylamine liquid with the skin causes severe skin burns, and high concentrations of the vapor cause severe skin irritation. High concentrations also produce severe eye damage. Contact with the liquid anhydrous material causes frostbite.
In addition to its own toxicity, burning or thermally decomposed trimethylamine liberates the deadly nitrogen oxides, a group of gases containing nitrogen and oxygen and possessing the general formula NO,.
Trimethylamine, although considered a stable chemical, reacts violently with several other chemicals, including acids, aldehydes, elemental metals from groups I and II on the periodic table (the alkali and alkaline earth metals), dithiocarbamates, epoxies, halogenated organic materials, nitrogen oxides, nitrous acid, oxidizing agents, peroxides, sodium nitrate, and strong reducing agents. It explodes on contact with bromine, ethylene oxide, and triethyl aluminum.
Remember that the water solution of trimethylamine is also a hazardous material. Under conditions of heat, agitation, or both, trimethylamine gas will be released from solution and be as dangerous as gas liberated from the liquefied gas—if not in as great a volume.
NONFIRE RELEASE
Identifying the released hazardous material is always important, but in the case of trimethylamine it is very important to know whether liquefied gas or the solution of gas in water is in the stressed or breached container. Both are hazardous materials, but more pure gas will be released if the container contains liquefied gas.
Any release of trimethylamine is serious, and a release of a significant amount should trigger the community’s local emergency plan as dictated by Title III of SARA (Superfund Amendments and Reauthorization Act of 1986). This plan should mobilize all the elements necessary to handle a major emergency in the community—not only the fire service and Red Cross. Among the most important (at least in offering advice to the incident commander at such a release) are the environmental experts who can advise on mitigation techniques that will minimize danger to the environment. Everyone, including the environmental authorities, realizes that life safety is the most important aspect of any emergency, but the environment ranks a close second in mitigation considerations. The manufacturer of the trimethylamine should be consulted for safe mitigation methods.
Since trimethylamine is a flammable gas, approach the incident ground and establish the emergency forces as you would with any flammable gas or liquid. Approach from upwind and provide for wind and weather changes—no matter how suddenly they might occur. Exclude all unauthorized personnel from the danger zone. Consider evacuation immediately for a radius of up to two miles, depending on the amount of the release or potential release. Eliminate all ignition sources, remembering that a hot engine could ignite material with an ignition temperature of only 374°F.
If liquefied gas is escaping from the container, it may be under considerable pressure. If the gas is escaping in an upward direction, consider that less gas may be present near the ground near the container than a little farther away. Attempts to patch the leak depend on the personnel available, their education and training, the equipment available, and—most important—the safety of the intended action. All entering an area where trimethylamine has been released must be totally protected—that is, a total encapsulating suit and positivepressure, self-contained breathing apparatus. All tools and equipment must be nonsparking and compatible with the product. No total encapsulating suit will protect against an explosion of the gas and the resulting fire.
Gas escaping from a container of the aqueous solution is expelled under less pressure than liquefied gas, and the hole (if small enough) therefore may be easier to patch. Remember that the gas escaping from the aqueous solution is just as hazardous as the gas from the liquefied gas, although there probably would be a smaller volume.
Since trimethylamine is so soluble in water, high-pressure spray and fog patterns can be used to sweep vapors from the air. Be sure to contain the water used in this technique, since it will be contaminated with trimethylamine.
Escaping gas quickly sinks to the ground and begins to move downwind or down low spots in the terrain if there is no wind. Being aware of the high-vapor density of the gas allows you to predict its movement. The gas is detectable by its powerful odor, which one reference says is present down to 0.21 ppb (parts per billion). Needless to say, evacuation procedures immediately must be carried out downwind and in a large radius around the leak.
Leaking liquefied gas immediately generates large amounts of the gaseous product, especially when it first contacts the ground. As the surrounding ground is cooled by the liquid, production of vapors may be slowed somewhat but not enough to be noticeable. Remember that the gas is now in an environment many degrees higher than its boiling point and that a liquid at its boiling point generates vapors at its maximum rate.
Again, high-pressure spray or fog may be used to dissolve vapors from the air. The runoff water not only must be contained but also must be kept from contacting the pool of liquefied gas, since contact speeds up the generation of gas by warming more of the cold liquid.
Applying alcohol foam may help slow the evolution of gas; foam manufacturers must be consulted to determine the type of foam to be used and its application procedures. The original contact of the foam with the cold liquid initially speeds evaporation, but it may work if the blanket is properly maintained. Then efficiency of the foam blanket must be measured against the warming action produced on contact.
Creating containment dikes or pits can prevent the spread of the cold liquid. Sparkproof and compatible tools and equipment always must be used. The smaller the liquid’s surface area, the slower the evolution of gas and the easier it is to cover the surface. Containment aLso allows for the possible salvage, subsequent cleanup, or both by professional salvage firms. Emergency responders should never perform salvage or cleanup activities. The sellers, buyers, and shippers of the product, all of whom should be notified of the release at the start of the incident, are much more capable of carrying out these activities in a safe manner. Containment dikes and pits should be used for releases of the liquefied gas and the aqueous solution.
All forms of the product can be salvaged by pumping the product into secure containers and removing them. Remaining materials may be absorbed by adding ash, clay, sand, soil, or other absorbent materials, which should be removed by salvage personnel. Remember that the contaminated sorbent material contains the hazardous material and is still dangerous. It must be disposed of in accordance with federal, state, and local regulations. This also is true of any contaminated soil or other material that comes in contact with the material during the incident.
Trimethylamine in liquefied gas and aqueous solution forms must be prevented from entering waterways and sewer systems. This can be accomplished by building dikes at catch basins, manholes, and any other natural entrances to waterways.
If the material enters a waterway, all downstream users must be notified at once. Trimethylamine floats on the surface and immediately begins to boil while starting to dissolve in the water, killing waterfowl and aquatic life and presenting an explosive situation downstream. If possible, the stream should be diverted to a holding area until aeration techniques such as sparging or air-stripping procedures can be accomplished. Activated charcoal can be added to the impounded water to adsorb the product. The material then must be disposed of in the same manner as other contaminated sorbents.
IDENTIFICATION NUMBERS AND RATINGS
CAS
(Chemical Abstract Services)
75-50-3
STCC
(Standard Transportation Commodity Code)
4905540, anhydrous material 4907880, aqueous solution
RTECS
(Registry of Toxic Effects of Chemical Substances) PA0350000, normal material YH2280000, anhydrous material YH2285000, aqueous solution
UN/NA
(United Nations/North America)
1083, anhydrous material 1297, aqueous solution
CHRIS
(Chemical Hazards Response Information System)
TMA
DOT
(U.S. Department of Transportation) flammable gas
NFPA 704 Rating
3-4-0
IMO
(International Maritime Organization)
2.1, flammable gas, anhydrous material
3.2, flammable liquid, aqueous solution
The environmental authorities decide when the water is safe for use. (Drinking is not the only use of the water, and any contaminated water unknowingly pulled into an industrial operation could result in an explosion. )
If the product enters a sewer system, notify all sewage treatment facilities immediately. The liquefied gas fills the sewer with flammable gas immediately. Gas from the aqueous solution produces more slowly but is just as dangerous. Gas forced out into the air—and therefore into its flammable range—anywhere along the sewer system could produce an explosion that travels throughout the system. In this case, the dilution technique might be effective; the sewers should be flushed with large quantities of water until the danger has passed Any small amounts remaining in the water may be removed safely by carefully executed aeration techniques at the sewage treatment plant. Again, the manufacturer of the trimethylamine and environmental experts should be consulted for safety reasons.
FIRE SCENARIO
All containers of trimethylamine that are not burning but are threatened by flames or radiated heat must be cooled by applying water with unmanned monitors from as far away as possible. If water cannot be applied without endangering firefighters, the technique should be abandoned and exposures protected. Firefighters never should get between the fire and containers of combustible or flammable material.
SYNONYMS
n,n-dimethyl, methyl amine methanamine, n,n-dimethyl TMA
trimethylamine, anhydrous trimethylamine, aqueous solution
Heated containers stressed by increased internal pressure should have pressure-relief devices operating. These sources of the gas ignite quite rapidly due to the low ignition temperature of the gas. The flames never should be extinguished unless the flow of gas can be stopped immediately after extinguishment. The length of the flame and the noise of the escaping gas should be observed. If the flame suddenly lengthens or the sound of the escaping gas suddenly rises in pitch, a BLEVE (boiling-liquid, expanding-vapor explosion) may be imminent. These danger signs do not always appear, and when they do, anyone near the container may not have time to escape. Care must be taken not to be in danger of being incinerated by the resulting explosion and fireball. The concussion or flying shrapnel can kill even those quite some distance away from the blast site.
Pools of burning trimethylamine may be extinguished by applying water spray or fog, alcohol-type foam, carbon dioxide, and dry chemical— depending on the size of the pool and terrain and weather conditions. Any water used to suppress the fire must be contained, so the size of the containment pond or pit must be considered. Water added to the burning pool may cause the burning product to flow away before it is extinguished, thereby spreading the fire. Water also may be added to cool and dilute the burning trimethylamine to a mixture with a very high flash point and effectively spread out the fuel in the water solution so that the fire goes out.
Since pure trimethylamine has such a low ignition point, reignition of escaping gas or liquid happens much more easily than with other materials. Any object heated to 374°F by the fire will be the ignition source once the fire has been extinguished.
PROTECTIVE CLOTHING AND EQUIPMENT
Contact with liquefied trimethylamine or its vapors must be avoided at all times. Only the material used in total encapsulating suits offers protection from the vapors, and the suits are in danger of becoming brittle and cracking if they come in contact with the cold liquid. Turnout gear may offer some protection against vapors if the sleeves and cuffs are taped down. Face shields, goggles, and rubber gloves and boots may offer short-term protection against vapors. Nothing is effective against the coldness of the liquefied gas, and no protective clothing will protect a firefighter against fire or explosion.
The manufacturers of total encapsulating suits must be consulted to determine if their products offer adequate protection against trimethylamine.
Inhalation. Move the victim to fresh air and keep him/her calm and warm. If 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. Call for immediate medical attention.
Eye contact. Flush the eyes immediately for at least 15 minutes, lifting the eyelids occasionally. Call for immediate medical attention.
Skin contact. Wash the affected areas of the body with large amounts of soap and water. If irritation continues after washing, seek medical attention.
Ingestion. If the victim is conscious, make him/her drink large quantities of water immediately, and induce vomiting. Never make an unconscious person try to drink anything or to vomit. Call for immediate medical attention
