Use Nationally and in Massachusetts
MDI is part of a family of isocyanate-based chemicals called "diisocyanates and polyisocyanates." MDI and toluene diisocyanates (TDI) are the primary isocyanates, accounting for 94% of U.S. isocyanate production capacity in 1998. ARCO Chemical, BASF Corporation, Bayer Corp., Dow Chemical, and ICI are the principal global producers of MDI and TDI. They account for 80% of worldwide capacity and are the only producers of MDI and TDI in the U.S. MDI and TDI are primarily intermediaries in the manufacture of urethane-based materials, especially polyurethane foams.
In 1996, U.S. manufacturers consumed 1.17 billion pounds of MDI in the production of polyurethane rigid foams (53% of total use), flexible foam, binders, elastomers, adhesives and sealants, surface coatings, and fibers.
- The primary uses of rigid polyurethane foam are as an insulating or cushioning material in construction applications, appliances, packaging, transportation, and industrial applications. "Transportation" includes board insulation used in trucks, trailers, and rail cars and energy absorbing foams in automobiles. "Industrial applications" includes insulation used on tanks, pipes, and ducts.
- Manufacturers occasionally use MDI in flexible polyurethane foams, often as a blend with TDI. End-users of flexible foam include producers of transportation equipment, furniture, bedding, carpet underlay, packaging, and textiles.
- MDI is used to produce polyurethane "binders" for linking wood chips and flakes together (e.g., oriented strandboard), sand together for use in foundry molds, and rubber chips and flakes together to create surface materials (e.g., outdoor sport tracks).
- Polyurethane elastomers include cast elastomers, microcellular products, and thermoplastic elastomers. Cast elastomer products include gaskets, shoe soles, mechanical parts, and wheels. Microcellular products include automobile parts (such as body panels, bumper covers, modular windows, and spoilers) and furniture. Thermoplastic elastomer products include extrusionproduced electrical cable jackets, flexible tubing and hose, film, and sheet and injection-produced cattle tags, hydraulic seals, instrument panels, and sport and recreational items.
- Polyurethane adhesives and sealants are used in automobile production, construction applications, packaging applications, and shoe production.
- Manufacturers also use MDI to produce polyurethane surface coatings and fibers.
Under the Massachusetts Toxics Use Reduction Act (MA TURA), MDI was reported as a specific chemical from 1990 to 1994.
(CAS 101-68-8) In 1995, a "Diisocyanates Category," which includes MDI and 19 other diisocyanates, was added to the list of reportable chemicals. This category does not include toluene diisocyanates (TDIs); they are still reported as specific chemicals. For this fact sheet, specific MDI data for 1990 and 1994 is provided, as well as Diisocyanates Category data for 1998 in Tables 1 and 2. Facilities listed in Table 2 which reported only in 1998 may be users of other diisocyanates, not MDI.
Between 1990 and 1994 MDI use in Massachusetts grew by 2.2 million lbs., or 33%, with Firestone Building Products accounting for 1.9 million lbs. In 1990, 15 facilities used MDI to produce polyurethane binders for foundry core sand molds, polyurethane elastomers for shoe soles and the inner cores of softballs, polyurethane adhesives, rigid foam for insulation and packaging, and spandex (see Table 2).
In 1998, 19 facilities reported using 5.6 million lbs. of Diisocyanates Category. The largest difference compared with earlier MDI quantities was the decrease due to Firestone Building Products, which ceased operations in Massachusetts. Increases relative to previous MDI quantities occurred in miscellaneous liquid urethanes, and polyurethane elastomers, fiber and adhesives.
Table 1 includes two sources of "output" data: MA TURA and U.S. Environmental Protection Agency (EPA), Toxics Release Inventory (TRI) data. The MA TURA database includes all nonproduct material created by a process line prior to release, onsite treatment, or transfer ("byproduct") and the amount of toxic chemical incorporated into a product ("shipped in or as product"). The U.S. EPA, TRI database includes information on the waste materials generated by a facility after on-site treatment including: releases to air, land, and water ("environmental releases") and transfers off-site for treatment or disposal ("off-site transfers").
Reported TURA Outputs of MDI increased dramatically between 1990 and 1994, due primarily to Firestone Building Products' change in how they reported MDI "shipped in or as product."
- Firestone reported no MDI as shipped in or as product in 1990, but reported all MDI used (7 million lbs.) as shipped in product in 1994.
In 1998, approximately 50,000 lbs. of Diisocyanates Category were reported as byproduct.
- Bostik, Inc. reported 19,000 lbs., and New Balance Athletic Shoes and Globe Manufacturing each reported approximately 10,000 lbs. of byproduct.
TRI environmental releases and transfers of MDI increased by 30% between 1990 and 1994.
- Environmental releases decreased by 90% between 1990 and 1994. Offsetting that were increases in off-site transfers.
SRI International, 1998, "Diisocyanates and Polyisocyanates" (see endnote #1 for complete citation); Massachusetts Department of Environmental Protection (MA DEP), 1998, "Massachusetts Toxics Use Reduction Act Chemical Reporting Data" (Boston: MA DEP).