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Reuse or Recycle of Residual HDI, IPDI, and HMDI

Erin Dickison

HDI (CAS# 822-06-0), IPDI (CAS# 4098-71-9), and HMDI (CAS# 5124-30-1) are not listed as a hazardous wastes under the Resource Conservation and Recovery Act (RCRA).

Review the Manufacturer’s Safety Data Sheets and all federal, state and local laws and regulations. Some considerations for managing residual HDI, IPDI, and HMDI for other beneficial uses include:

Liquid Decontaminant and Disposal of Empty HDI, IPDI, and HMDI Containers

Residual HDI, IPDI, and HMDI material can be reacted with a liquid decontaminant. The residual HDI, IPDI, and HMDI is added slowly or in increments under mechanical stirring to the decontaminant, which is contained in an open-top drum. Care should be taken to conduct this process in a well-ventilated area or outdoors (this may require air permitting in some states) and follow the manufacturer’s guidance for appropriate personal protective equipment. Allow the reacted material to stand for the period recommended by the manufacturer, which is typically 48 hours to permit evolved carbon dioxide to escape.

Decant the liquid and determine the disposition of both the solid and liquid products in accordance with all relevant federal, state and local laws and regulations. Refer to the Manufacturer’s recommendations on how to decontaminate HDI, IPDI, or HMDI drums.

Drums destined for a scrap dealer, an incinerator, or alternative options must be decontaminated, then punctured or crushed to prevent reuse.

There are five procedures for disposing of drums that have contained HDI, IPDI, or HMDI. They may be sent to:

  • a reconditioner,
  • a scrap metal dealer,
  • an approved incineration facility,
  • a material reclamation processer, or,
  • an approved landfill that complies with all federal, state and local laws and regulations. Note: It is important to understand whether the landfill has any special restrictions. For example, certain landfills have a ban on accepting recognizable drums and other containers over a certain size. In some cases, processors may be able to destroy the drums (i.e., using a drum crusher) and send them to a landfill. Still, sending empty drums to a landfill can pose long-term liability issues if the landfill is ever found to be contaminated. Careful diligence is warranted when using this procedure.

Another consideration is to arrange with the raw materials supplier to accept return drums. Some processors have found that receiving raw materials in returnable shipping containers (i.e., totes) instead of drums is a viable option.

Regardless of the procedure used, empty all drums (as defined by RCRA, 40 CFR § 261.7) before they leave the HDI, IPDI, or HMDI user’s facility. Drums to be sent to a reconditioner may also need to be decontaminated. However, since reconditioners use a variety of techniques to clean drums and to prepare them for reuse, consult with the reconditioner before using any drum decontamination procedure.

WARNING: Empty drums are not to be burned or cut open with a gas or electric torch, as toxic decomposition products may be liberated.

Resources on Disposal of HDI, IPDI, and HMDI

Here are some helpful resources from the Center for the Polyurethanes Industry (CPI) on how to dispose of polyurethane chemicals:

Government and Other Resources

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