8. Emergency Procedures

Guidelines for Dealing with MDI Product Incidents

All incidents are unique so it is not possible to write guidelines to deal with every circumstance. Each incident must be assessed from the information available.

All people involved with the handling or transportation of MDI must be aware of the hazards associated with MDI, the appropriate emergency procedures, and their individual responsibilities in the event of any emergency involving MDI.

The primary response to any release of MDI, whether a transportation incident or an in-plant spill, is to evacuate all unprotected people to a safe location. Only then should properly trained and protected personnel (see Section 5) evaluate, contain, stop, clean up, and decontaminate any spill. The odor threshold of MDI is above the established exposure limits for MDI. Areas should not be considered free of diisocyanate vapors until the area has been monitored.

Depending upon the size, location, and type of release, government agencies or authorities may require notification. In the United States, transportation incidents of over 5,000 lbs. to the environment must be reported to the National Response Center (NRC) (1-800-424-8802) and the local planning commission as outlined under Emergency Planning and Community Right-to-Know Act (EPCRA) regulations. Transportation incidents involving MDI must be reported to the NRC for any release over the reportable quantity of 5,000 lbs. (approximately 500 gallons). This is a requirement of United States Federal Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) regulations. Regulations involving the release of hazardous chemicals are continually evolving, therefore, it is important that all companies handling MDI be aware of the current legislative requirements in each jurisdiction.

Each plant should have a system for dealing with emergencies within the plant. Such systems are only effective if regularly practiced. It is appropriate to form a plant fire crew and emergency team so a well-trained team can quickly address an emergency. Everyone, however, should be aware of the hazards involved and the limitations of self-help. The top priority should always be to save a life rather than limit physical damage.

Spill and Leaks

Only properly trained and equipped personnel (see section 5) should attempt to clean up spills and leaks. The spill should be contained, and the leak stopped to prevent further contamination. It is necessary to distinguish between minor incidents, such as those that may occur in a laboratory or a workshop handling MDI regularly, and major spills, such as a bulk tank truck release. The most important criteria for distinguishing between the two is the ability of present personnel to deal with the occurrence, rather than the actual size of the release.

Minor Incidents

For small spills or leaks, trained people wearing appropriate PPE and respiratory protection should ventilate the area by opening doors and windows, then completely cover the spill with an absorbent material such as an all-purpose oil absorbent, dry sand, or cat litter.

Use more than enough absorbent material to absorb all of the liquid MDI. Shovel or scoop the absorbent into an open top container and move to a safe location for neutralization. Do not tightly seal this container since the MDI will react with any moisture present and generate CO2 gas, which could cause a sealed container to burst.

Decontaminating or neutralizing solutions are mixtures of agents that react with the MDI and agents that promote the reaction. The choice of solution will depend on the location (inside or outside), temperature (below or above freezing), and the flammability requirement for the intended use. A typical decontaminating solution can be made by mixing water (90-95 vol%), household ammonia (3-8 vol%), and liquid detergent (1-7 vol%). The water and ammonia will react with the MDI to form polyurea solids and CO2 gas, and the detergent helps promote the reaction. Soda ash (Na2CO3) may be used instead of ammonia resulting in a less active decontamination solution. This solution works well indoors at room temperature. It is important to note the hazards and regulatory limitations of any neutralizing solution.

After the drums containing the shoveled sorbent material are moved to a safe area, apply neutralizing solution and allow it to stand with a loose-fitting cover at least 48 hours. The container may be sealed after 48 hours. The container should remain vented (loosely covered) to prevent any pressure buildup, and the contents of the container properly disposed (see Section 9).

After the absorbent has been removed from the spill site, the site should be washed and scrubbed with neutralizing solution. Allow the solution to react for at least ten minutes. Once the area is cleaned it should be tested for diisocyanate vapors. If MDI vapors continue to be present, the decontamination should be repeated until the area is free of MDI vapors.

Solid neutralizers, which are neutralizers premixed with an absorbent, may be used for the quick clean-up of very small spills.

Ammonia may be regulated as a hazardous material. Before using ammonia, refer to any exposure limits and applicable regulations. The use of sawdust in combination with any decontaminate solution may cause auto-ignition.

Large Spills

For large spills of MDI, immediate emergency response is necessary to contain the release. This may require notification of local emergency response services such as the fire department. Such an event should be factored into every MDI user’s community awareness program.

All persons should be evacuated to a safe location. Properly trained and equipped personnel should then isolate and contain the spill. MDI should be contained and not be allowed to flow into any sewers or waterways.

Once the spill has been isolated and contained, the appropriate clean-up procedures should be used to remove and decontaminate the MDI. Transfer as much liquid as possible via pump or vacuum device into closed but unsealed containers for disposal. Absorbent material and decontaminating solution should then be used as described in the previous section regarding minor spills to clean the area. For specific instructions or assistance, the BASF emergency help line is available 24 hours a day in the United States (1-800-832-HELP).

For transportation incidents in the United States, the American Chemistry Council (ACC) operates CHEMTREC. The CHEMTREC number (1-800-424-9300) is available 24 hours a day and is on all BASF Bills of Lading and SDSs. A call to CHEMTREC will set the emergency response notification process in motion as well as provide emergency response information to response personnel. A list of emergency response contact numbers for the United States, Canada and Mexico can be found in Section 1 of this handbook.

MDI Involved in Fires

All involved personnel must put on self-contained breathing apparatus and complete chemical protection (i.e., rubber gloves, boots, goggles, and protective clothing). All nonessential personnel must evacuate the immediate area. The fire should be extinguished using one of the following:

1. Dry chemical powder
2. Protein-based foam 
3. CO2 extinguisher 
4. Large quantities of water

Once the fire is extinguished, the next step is to prevent spilled material from spreading by using collection containers and absorbers such as sand or earth.

The use of water or foam to extinguish the fire and cool the container makes it likely that moisture will enter the
damaged tank or drum. Since water reacts with MDI to form solid polyureas and CO2, the danger exists of the damaged area becoming plugged, resulting in pressure buildup. To prevent damage to the tank, it must be vented.

Depending on the condition of the tank and/or vehicle, the MDI product should be transferred to another container for disposal. This new tank must also be vented. In any case, the MDI product should not be shipped until the degree of water contamination is clarified.

If the MDI product is stored in the vicinity of a fire but not directly involved in the fire, the container should be moved clear of the area. If the container or tank cannot be moved away from the fire, a water curtain should be positioned between it and the fire. If this cannot be accomplished safely, the tank should be cooled using a direct water spray. This should prevent damage to the tank body and its contents.

Pressurized Drums

A bulging drum of MDI should be assumed to be the result of contamination of the product, usually with water. This slow but  unstoppable reaction with a diisocyanate produces CO2, which increases the pressure inside the container. Since it is not easy to judge the acute risk of bursting, the drum under pressure should not be moved. A tarpaulin tarp should be placed over the drum.

It is necessary to relieve the pressure safely before the drum bursts. This is best accomplished by puncturing the top of the drum with a long-handled spike. Some response companies have specialized drum puncturing devices. During this action, all uninvolved persons must be removed from the area and the working personnel must have complete chemical protection.

The punctured drum must then be placed in an oversized drum with pressure venting capabilities. Remember that the original contamination will probably continue to cause a pressure increase, so the container must be regularly vented using proper precautions. Contact BASF for disposal recommendations.

Chemical Reactions

The combination of polyol and diisocyanate components yields large amounts of heat and gas evolution. An evacuation of the immediate surroundings should be considered because of the potential large amounts of heated MDI vapors that can be evolved. All personnel involved must wear complete protective equipment. The reaction, once begun, cannot be stopped and the goal must be to prevent pressure buildup by venting. In most instances, controlled venting via the safety valve may not be possible due to the safety valve becoming plugged with foam or solids. If possible, stop uncontaminated material from entering the reaction by pumping it into a separate vessel.

Although difficult with insulated tanks, cooling should be attempted. Any vapors should be knocked down with water spray or foam. The reaction should proceed to end with a minimum of heat and vapor evolution.