CARBON DISULFIDE
HAZARDOUS MATERIALS
CHEMICAL DATA NOTEBOOK SERIES #52
Carbon disulfide (also known as carbon bisulfide) is a flammable, toxic, slightly corrosive, reactive, irritating, clear, colorless liquid with an odor like rotten cabbage. It is a relatively inexpensive material with good solvent properties, which makes it a popular industrial material. In addition to its use as a solvent, it is used as a fumigant and as a raw material in the manufacture of several classes of products such as cellophane, dyes, matches, pesticides, paper, pharmaceuticals, optical glass, rayon, rubber, and soil conditioners.
Carbon disulfide has a flash point of – 22°F, an ignition temperature of 212°F (at least one reference has it as low as 194°F), and a flammable range of from 1 percent to 50 percent. It has a specific gravity of 1.26, a molecular weight of 76, and a vapor density of 2.63. It boils at 115°F, freezes at — 168.4°F, and is slightly soluble in water. Its molecular formula is CS2.
HAZARDS
Carbon disulfide is an extremely flammable liquid according to all measurements of how easily a liquid burns: A flammable liquid is a liquid whose flash point is below 100°F, and carbon disulfide’s flash point is
— 22°F. This means that at any temperature above — 22°F, carbon disulfide evolves vapors sufficient to form an ignitable mixture with the air near the surface of the liquid, and any release will be extremely hazardous and followed by an explosion and fire. Its flammable range of 1 percent to 50 percent means that the lower flammable limit will be reached almost immediately, while it will be somewhat difficult for the vapors to become too rich, or pass the upper flammable limit.
As if the extremely low flash point and very w ide flammable range don’t make carbon disulfide enough of a hazard, its ignition temperature of 212°F (one reference has it as low as 196°F) is the lowest of any common flammable liquid. The energy released from steam or a lit incandescent light bulb can cause carbon disulfide vapors to ignite. Most emergency responders only consider a fire when a flammable liquid reaches its ignition temperature, but an explosion occurs first. The size and strength of the explosion are directly proportional to the amount of vapors present when ignition occurs, all other conditions — temperature, humidity, and so on — being equal.
Carbon disulfide is a toxic material, and inhalation of vapors in a concentration of 1,150 ppm (parts per million in air) causes such serious symptoms as eye and nose irritation, dizziness, drop in blood pressure, headache, nausea, and unconsciousness. Carbon disulfide’s main toxic effect is on the central nervous system, where it acts as a narcotic and anesthetic. Concentrations as low as 4,800 ppm can cause death in 30 minutes. Lower concentrations and chronic exposure to these levels can cause serious problems in the cardiovascular, nervous, and reproductive systems, with possible permanent eye problems. Its TLVTWA (threshold limit value) is 10 ppm.
Skin contact with liquid carbon disulfide causes irritation and blistering, depending on the length of the contact. Prolonged contact causes burning. The material is absorbed through the skin, contributing to different systemic problems.
Any contact of liquid carbon disulfide with the eyes causes severe irritation and possible permanent damage. Ingetion of the liquid causes convulsions, diarrhea, headache, vomiting, coma, and death, depending on the amount ingested.
Carbon disulfide is reactive with many classes of chemicals including acids, amines, azides, bases, imines, active metals (and some of their compounds) as well as the nitrogen oxides, permanganates, and other strong oxidizers. It also reacts with aluminum, chlorine, fluorine, and zinc. Explosive salts may be formed when carbon disulfide contacts certain oxides. Keep in mind that each class of chemicals mentioned above may contain dozens of chemicals that react with carbon disulfide. Carbon disulfide may be corrosive to aluminum, zinc, other active metals, and some rubber and plastics.
NONFIRE RELEASE
As in any hazardous-material release, notify the proper environmental authorities. They can give extremely valuable advice. They have the same concern as emergency responders—-human safety.
Any release of carbon disulfide should be contained as quickly as possible to reduce the surface area of the spill. This will reduce vapor generation and restrict land contamination. A containment dike may be constructed of clay, sand, soil, or other materials. A containment pit may be dug to hold the product if equipment is available to do so. All tools and equipment should be compatible and nonsparking. The engine of a backhoe and similar equipment are possible ignition sources, so beware of an explosion and fire hazard.
The greatest danger is from the vapors generated as the liquid evaporates. Consider evacuation downwind first. The high vapor density of carbon disulfide (2.63) means it will “hang together” and flow along low spots in the ground. It has a tendency to accumulate in enclosed and/or low areas, and even the slightest energy source will set off an explosion. In addition, anyone without respiratory protection who gets caught in high concentrations of the vapors will be exposed to the health hazards mentioned earlier.
The application of firefighting foam to the surface of carbon disulfide will slow vapor generation. The application and reapplication of the foam as it breaks down will add to the volume of the liquid and must be contained. Another technique to retard generation of vapors is to cover the carbon disulfide with a layer of water. This is only an option if the added volume will not cause runoff of contaminated water. Covering the spilled liquid with a compatible material is another technique to slow evaporation. The use of high-pressure water spray or fog will disperse any released vapors, but that water will then be contaminated and must be contained.
In some instances vacuuming equipment may be available to pick up the spilled liquid and carry it to secure containers. Such equipment must be compatible with such a dangerous liquid as carbon disulfide. In many cases the manufacturer of the product, the shipper, and/or the consignee may provide equipment. In all cases leave salvage of the product to professionals: Emergency responders never should become involved with salvage or cleanup.
Once the liquid has been suctioned into secure containers, the remaining liquid may be absorbed by clay, cement, powder, fly ash, peat moss, sand, soil, or commercial sorbents. These materials, as w ell as all contaminated soil, must be removed under supervision of the environmental authorities and disposed of in accordance with local, state, and federal regulations. The environmental experts will have the final determination of whether a spill site has been cleaned properly.
IDENTIFICATION NUMBERS AND RATINGS
CAS
(Chemical Abstract Services)
75-15-0
STCC
(Standard Transportation Commodity Code)
4908125
RTECS
(Registry of Toxic Effects of Chemical Substances)
FF6650000
UN/NA
(United Nations/North America)
1131
CHRIS
(Chemical Hazard Response Information System)
CBB
RCRA
(Resource Conservation and Recovery Act)
P022
DOT
(U.S. Department of Transportation)
Flammable Liquid
NFPA 704 Rating
2–3-0
IMO
(International Maritime Organization)
3.1, Flammable Liquid
All attempts must be made to keep carbon disulfide from entering sewers or waterways. If it does, notify all downstream users of the water or sewage treatment plants immediately. The surprise arrival of such a material can produce explosions almost anywhere.
If there is no water in a sewer that the product enters, the sewer will quickly fill with the rapidly evaporating liquid. Carbon disulfide’s high vapor density means that the vapors will flow downhill, following the grade of the sewer. Some of the vapors may be forced out of the sewer through catch basins or manhole covers and may accumulate in streets or other areas subject to ignition sources (such as automobile engines). This explosion hazard may exist at some distance from the spill. Its very wide flammable range also means that an explosion could occur in the sewer in those areas where up to SO percent of the air has been replaced by carbon disulfide vapors. Again, the only element missing is an ignition source.
If carbon disulfide enters a waterway, the liquid will sink to the bottom and very slowly dissolve. If the waterway is a fast-moving stream, the undissolved liquid will “roll” along the stream bed. On the other hand, if the stream is slow-moving, or the product enters a lake or pond, it will tend to How to a low spot and accumulate. The product may be pumped or suctioned to secure containers from the slow-moving stream or stationary water.
In the rapidly moving water, a dam can be built that will allow water to flow over it while it keeps the carbon disulfide on the bottom of the stream so it can be pumped. Or you can build a diversion dam to divert the contaminated water to a low-lying area for containment.
In the case of slow-moving streams, ponds, lakes, or diverted flow, sparging, air stripping, or other aeration techniques can be used to remove carbon disulfide. These techniques will release carbon disulfide vapors from the water —vapors that pose an explosion hazard.
In some instances, adsorption onto activated carbon may be effective. The carbon must be mixed into the water properly to be able to capture the product. The carbon may later be removed by dredging the water bed or pumping the water through a filter on shore. The spent activated charcoal w ill now have the product on its surface and will have to be handled carefully and disposed of in accordance with federal, state, and local regulations.
If the product has entered a w aterway. the environmental officials will monitor the degree of contamination and determine if contained w ater can be released. They also will determine if and when the w aterwav is free of contaminants and safe for normal use.
FIRE SCENARIO
All containers of carbon disulfide must be protected from the heat energy radiated from a fire or conducted by impinging flame. The evaporation rate of all liquids is increased as the temperature increases, and pressure within the container will rise rapidly. If the pressure rise is faster than can be controlled by a pressure relief device (if one is present), catastrophic failure of the container will occur, accompanied by a fireball, intense heat, and shrapnel. You can cool containers by applying water, but do so from as far away as possible with unmanned appliances.
Radiated heat may ignite carbon disulfide vapors rather easily, and those vapors will “flash” back to the material released from the container. The high vapor density means that the vapors will flow a long way and that the flashback may be explosive for some distance.
You can use dry chemicals, carbon dioxide, or foam to attack a pool of burning carbon disulfide, depending on the size of the fire and its location. Foam may be ineffective at preventing reignition, however. Consult the manufacturers of firefighting foam to determine what foam to use and howT to apply it. If the pool of liquid is contained, a layer of water floated over the top of the burning liquid may extinguish it, assuming that there will be no runoff.
With such a low ignition temperature, extinguished carbon disulfide may reignite easily because of the presence of metal or some other material that has been heated to 212°F by the recent flames. Do not attempt to salvage the product or clean up the area until all objects heated by the fire have cooled to ambient temperatures. Remember that the hot liquid is still producing explosive vapors and that your apparatus is a potential ignition source.
FIRST AID
For inhalation, move the victim to fresh air and keep calm and warm. If the victim’s breathing has stopped or has become labored, administer artificial respiration (such action might expose the first-aid giver to the material in the victim’s lungs and/or vomit). Seek immediate medical attention.
SYNONYMS
carbon bisulfide
carbon bisulphide
carbon disulphide
carbon sulfide
carbon sulphide
dithiocarbonic anhydride
NCI-c04591
sulfocarbonic anhydride
sulphocarbonic anhydride
Weeviltox
For eye contact, flush the eyes immediately for at least 15 minutes, lifting the eyelids occasionally. Immediate medical attention is required.
For skin contact, wash the affected body areas with large amounts of soap and water. If irritation continues after washing, seek medical attention.
For ingestion, make conscious victims drink large quantities of water immediately and induce vomiting. Never try to make an unconscious person drink or vomit. Seek immediate medical attention.
PROTECTIVE CLOTHING AND EQUIPMENT
Select protective clothing and equipment that prevent contact of carbon disulfide with the eyes and skin. Rubber gloves, aprons, and boots may offer skin protection. Wear splashproof chemical goggles to protect eyes. Use positive-pressure, selfcontained breathing apparatus for respiratory protection. Manufacturers of total encapsulating suits say that suits made of polyvinyl alcohol, polyethylene/ethylene vinyl alcohol laminates, and in some instances Viton will offer protection for some period of time. Contact individual manufacturers to find out the degree of safety of each recommended material.
