CHEMICAL DATA NOTEBOOK SERIES #93: METHYL ISOBUTYL KETONE
HAZARDOUS MATERIALS
Methyl isobutyl ketone is a flammable, moderately toxic, irritating, clear, colorless liquid with a pleasant odor. It is used as a denaturant for ethyl alcohol, an extractant of uranium from fission products, a solvent for many industrial processes, and a raw material in the manufacture of other chemicals.
PROPERTIES
Methyl isobutyl ketone is a flammableliquid with a flash point of 64°F, an ignition temperature of 840°F, and an explosive range of 1.4 to 7.5 percent in air. Its specific gravity is 0.8, its molecular weight is 100, and its vapor density is 3-45. Its boiling point is 24l°F, its freezing point is — 1 19°F, and it is somewhat soluble in water. Its molecular formula is (CH
HAZARDS
Flammability is methyl isobutyl ketone’s major hazard. Its volatility is such that it can reach its lower explosive limit of 1.8 percent fairly quickly. Its flash point of 64°F means that it is a hazard at rm temperature, quickly producing vapors sufficient to form an ignitahlc mixture with the air. Its ignition temperature of 840°F means that any common ignition source can ignite its vapors. A vapor density of .3-45 means that the vapors are very dense (3-45 times heavier than air), which means that when released from a container or upon evaporating from a poo! of released liquid, the vapors will fall and “hug” the ground. Vapors are fluids; they will flow along low spots in the ground and may end up accumulating in low-lying areas or confined spaces.
Even though an accumulation of methyl isobutyl ketone vapors may produce a concentration higher than 7.5 percent (its upper explosive limit), the accumulation still presents a very dangerous explosivesituation. While it is true that gase-s and vapors cannot be ignited in concentrations outside their explosive ranges and that above the upper explosive limit there is not enough oxygen to support combustion, an explosion can occur if an ignition source presents enough energy to raise a small part of the vapors to ignition temperature. This almost always occurs outdtx»rs or when a dr in a r containing the vapors is opened. Outside, there is almost always some air movement, even if it is caused by a person moving into the accumulation of vapors. And inside, when a dr is opened, the air moves considerably. The point is, any movement of air maychange the concentration of flammable gases or vapors (of any flammable or combustible liquid) just enough to mix in enough air to bring the concentration down below the upper explosive limit and therefore into the explosive range. In addition, even if the concentration of vapors is extremely high, vapors near the edge of the accumulation will be in the explosive range so that if an ignition source were present here, the entire accumulation of vapor would expkxle.
An explosion always occurs when a flammable gas or vapor (or dust or fume, for that matter) is ignited. The terms upper flammable limit, lower flammable limit, flammable gas, flammable liquid, and combustible liquid always represent the act of burning and therefore may be fatally misleading. Because a flammable gits or the vapor from a flammable or combustible liquid may lxwithin the flammable range, a fire might lxthe first event to be expected when such gas or vapor is ignited. Ihis does not hapfien. Any accumulation within the flammable range of any gas, vapor, dust, or fume that burns will explode on ignition. The fire usually txcurs right after the explosion, if there is anything left to burn. It is a shame that the fire service ds not universally use and accept the terms upper and lower explosive limits.
Methyl isobutyl ketone is mtxlerately toxic to humans. Its TI.V-TWA (threshold limit value-time weighted average) is 50 ppm (parts per million of air), and its STHL (short-term exposure limit) is 75 ppm for 15 minutes. Exposure to methyl isobutyl ketone vapors will irritate the eyes, nose, and throat. Inhaling high concentrations of the vapors may cause breathing difficulties and can depress the central nervous system and cause dizziness, drowsiness, headache, narcosis, nausea (exposure to 100 ppm), staggering, unconsciousness, and eventually death.
Exposure to the vapors will severely irritate the eyes, prtxlucing tearing and pain. The txlor of methyl isobutyl ketone vapors can be detected at levels from as low as 0.5 to 8 ppm. The danger of explosion from the movement of methyl isobutyl ketone vapors described above can be repeated as exposure hazards for emergency responders or other individuals who might enter an area with a high concentration of vapors without the proper respiratory protection. Intoxication caused by inhaling the vapors may prevent exposed personnel from escaping the area, even if they are still conscious and appear to lxin control of their faculties. Depression of the central nervous system might impair the judgment of the exposed individuals, and the resulting confusion could prove fatal.
Repeated contact of the liquid with the skin will cause severe irritation and chemical burns. Exposing the skin to high concentrations of the vapors also will severely irritate the skin through defatting, causing the skin to inflame, crack, peel, and become subject to infection.
Data concerning the toxic effects of ingesting methyl isobutyl ketone are sparse, but some tests on animals have indicated a relatively low order of toxicity.
Although methyl isobutyl ketone is a stable chemical, it will react violently with all strong oxidizing agents.
NONFIRE RELEASE
Any large release of a hazardous material should put into motion the community’s local emergency response plan. However, since the major hazard of methyl isobutyl ketone is its flammability and the resulting explosion threat, the emergency response, at least initially, may be made up entirely of fire personnel. The potential for contamination of land and water must be considered; therefore, environmental authorities must be included in this and any other release of hazardous materials.
As always, emergency responders must approach the release from upwind and uphill, if possible, and all potential ignition sources must be eliminated immediately. Since the vapors of methyl isobutyl ketone are so dense, a major explosion hazard exists at all times, especially when potential ignition sources exist near the ground. This severe explosion hazard will be present until the source of the vapors has been removed and the vapors have dissipated. Because of this explosion hazard, evacuating all persons downwind must be considered immediately, probably while emergency responders are en route to the scene.
Attempts must be made to keep the flammable liquid from spreading, accomplished most simply and effectively by damming up the spilled liquid by forming dikes with peat, sand, soil, or other materials capable of preventing the flow of the liquid.
A more complicated method of containment is to dig a pit to hold the liquid, an approach that necessitates more sophisticated equipment (such as a backhoc) and tls and skilled operators than might be available. Recognize the potential for subterranean spread of the liquid in some soils. Its major advantage is that a pit usually has a smaller surface area exposed to the atmosphere. The general rule is, the rate of evaporation of identical liquids at identical agitation rates and temperatures will always be slower for the liquid presenting the smallest surface area to the atmosphere. Also with the pit, a smaller (but deeper) surface area will have to be covered to reduce evaporation. With the containment pond method, on the other hand, the contaminated soil can be removed more easily, since contamination is spread over a larger area. Nevertheless, any equipment or tools used for containment must be sparkpr, and motors or engines must be carefully monitored to avoid their igniting the vapors.
Once the liquid has been contained, salvage teams provided by the seller, the buyer, the shipper, or the manufacturer (or a combination) can salvage the product by suctioning the liquid into safe and secure containers. Any product left behind may be absorbed by clay, cement powder, fly ash, sand. soil. peat, or any other appropriate sorbent. The contaminated soil then must be removed (under direction of the environmental authorities) and disposed of in accordance with federal, state, and local regulations. Any absorbed material must be treated as hazardous, since any evaporation of the methyl isobutyl ketone represents a fire and explosion hazard. Under no circumstances should firefighters be involved in the salvage or cleanup at a hazardousmaterials incident unless they have been properly educated, trained, and equipped to handle these hazardous tasks.
The surface of the contained liquid may be blanketed with alcohol-type firefighting foam to slow vapor evolution. This will add to the volume of contained liquid and must be considered when using this mitigation technique (less foam will be required if a pit is dug, again because of the smaller surface area). The foam may have to be replenished from time to time.
If the surface of the contained release is small enough, sheeting or covers of compatible material may be spread over the liquid to slow and contain vapor evolution.
If no wind is present, the methyl isobutyl ketone vapors will slowly move downgrade. These slow-moving vapors may be dispersed with high-pressure water spray or fog, which will break them up safely and eliminate the danger of explosion. Contain all water used in this technique as contaminated liquid.
As in the case of any released liquid hazardous material, the purpose of the containment pond or pit is to prevent the released liquid from spreading its hazard or contamination. Efforts must be made to keep the methyl isobutyl ketone from entering any sort of system, such as a lake or pond, a moving waterway, or a sewer system, that would spread this hazard and contamination.
If any methyl isobutyl ketone enters a sewer system, it will present an explosion hazard throughout the area served by the system, especially downstream. Block all possible entries to the sewer system. Any methyl isobutyl ketone entering a sewer will float on the water, move downstream as it dissolves in the water, and evaporate all the while. These methyl isobutyl ketone vapors will move downward along the slope of the system, and some of the vapors might even be forced uphill for a short distance if the liquid is warm and evolving a great quantity of vapors. Any opening downstream caused by the product’s entry into the system will provide the same explosion hazard as that in the above-mentioned scenario, in which the vapors, no matter how highly concentrated in the confined area, will be within the explosive range at the edge of their confinement where they meet “fresh air.” Any ignition source here w ill ignite the vapors, causing an explosion all along the system at points where enough vapors are present. Notify all downstream water treatment facilities immediately.
Similarly, prevent liquid methyl isobutyl ketone from entering a moving waterway or stationary body of water. Any product entering a pond or lake slowly will spread over the surface, evaporating as it dissolves. The vapors will spread out evenly over the surface of the water if there is no breeze to disperse them.
In a river, stream, or other moving body of water, the agitation of the water as it moves downstream will speed up the dissolving of the product into the water. This agitation also will force vapors out of the water into the air. This production of vapors, plus the “normal” evaporation of the liquid floating on the water’s surface, will produce sufficient vapors to enter the explosive range. The heavy vapors most likely will stay within the confines of the waterway’s banks, moving the danger of an explosion downstream as the vapors seek an ignition source.
Notify all dow nstream users of the w’ater immediately. Any methyl isobutyl ketone vapors draw n into a closed space w ill be an extreme explosion hazard. Any water contaminated with this product draw’n into an industrial process in all likelihood will cause dissolved product to be forced from the water, creating an explosion hazard.
IDENTIFICATION NUMBERS AND RATINGS
CAS
(Chemical Abstract Services)
108-10-1
STCC
(Standard Transportation Commodity Code)
4909245
RTECS
(Registry’ of Toxic Effects of Chemical Substances)
SA9275000
UN/NA
(United Nations/North America)
1245
CHRIS
(Chemical Hazard Response Information System) MIK
RCRA
(Resource Conservation and Recovery Act)
U161
DOT
(U.S. Department of Transportation) Class 3, flammable liquid
NFPA 704 Rating
2-3-0
IMO
(International Maritime Organization)
3.2. flammable liquid
Environmental authorities must constantly monitor all water previously contaminated to determine its safety and fitness for use. They also will suggest ways to prevent the contamination from spreading, such as diverting the contaminated water into a low-lying holding area for agitation or other techniques for removing the contaminant safely. These and other experts will be of invaluable assistance to the incident commander throughout the incident.
FIRE SCENARIO
Handle incidents involving methyl isobutyl ketone as you would most other cases of released flammable liquid. Any increase in heat energy absorbed by the pool of liquid will speed up evaporation, causing more fuel to be spread into the atmosphere, increasing the chances of an explosive ignition of vapors. Should a container of methyl isobutyl ketone be exposed to the radiant heat of a fire or flame impingement, cool the container with straight streams of water delivered from unmanned appliances stationed outside the danger area that would be produced if the container exploded. Treat the containers as any other container of flammable liquid being exposed to heat.
Never allow yourself to come between a fire and containers holding gases or liquids, especially those that burn. Although catastrophic failure of the methyl isobutyl ketone container would not he likely if the safety-relief device is operating properly, there is always the possibility that it will fail or that the pressure rise within the container may be too rapid for the pressure-relief device to keep the pressure below the design strength of the container. Remember O’Brien’s Law: Murphy was an optimist!
Alcohol-type firefighting foam, carbon dioxide, dry chemical, or high-pressure water spray or fog can be applied to extinguish burning ptxds of methyl isobutyl ketone (straight streams might spread the burning liquid around as it floats on the surface of the water ). The extinguishing agent and method selected will depend on the quantity of material burning, the weather, the wind, the topography, and the availability of each agent.
PROTECTIVE CLOTHING AND EQUIPMENT
Select protective clothing and equipment that will provide maximum respiratory, eye, and skin protection against methyl isobutyl ketone. Regular turnout gear impervious to penetration by liquid materials may provide skin protection. Rubber boots, gloves, aprons, coveralls, and hoods may offer protection. Wear splashproof chemical goggles and full face masks for eye protection. Total encapsulating suits may not be required. If department standard operating procedures call for total encapsulating suits, contact the manufacturer of the department’s suits to determine the degree of protection they provide against methyl isobutyl ketone. Compatible materials may include butyl rubber, nitrile-butadiene rubber, polyethylene, polyurethane, and polyvinyl alcohol. Other references add Teflon® and polyethylene/ethylene vinyl acetate to the list. In any case, positive-pressure, selfcontained breathing apparatus is required for proper respiratory protection.
SYNONYMS
hexanone
hexone
isobutyl methyl ketone
isopropyl acetone
isopropyl methyl ketone
2-methyl’4-pentanone
4-methyl*2-pentanone
4-methyl-2-oxopentane
MIBK
MIK
FIRST AID
Inhalation of vapors. Move the victim to fresh air; keep him/her calm and w arm. 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. Obtain immediate medical attention.
Eye contact. Flush the eyes immediately for at least 15 minutes, lifting the eyelids occasionally. Obtain immediate medical attention.
Skin contact. Remove contaminated clothing and wash the affected body areas with large amounts of soap and water. Medical attention may be required.
Ingestion. There is disagreement about whether vomiting should be induced if the victim is conscious. Never try to make an unconscious person vomit or drink anything. Obtain immediate medical at-‘ tention.
