U.S. Environmental Protection Agency April 2011

1 Methylene Diphenyl Diisocyanate (MDI) And Related Compounds

Action Plan [RIN 2070-ZA15]

I. Overview

This Action Plan addresses the use of methyl ene diphenyl diisocyanate (MDI) and related compounds (See Appendix 1) in products that ma y result in consumer and general population exposures, particularly in or around buildings, including homes a nd schools. Diisocyanates are

well known dermal and inhalation sensitizers in the workplace and have been documented to cause asthma, lung damage, and in severe cases, fatal reactions. This Action Plan focuses on the potential health effects that may result from expo sures to the consumer or self-employed worker while using products containing uncured (unreac ted) diisocyanates (e.g., spray applied foam sealants, adhesives, and coatings ) or incidental exposures to th e general population while such products are used in or around buildings includin g homes or schools. In conducting this review of MDI compounds, EPA considered a number of potential actions, includi ng regulatory actions under TSCA sections 4, 5, 6, and 8; cooperative actions with other federal agencies; and voluntary actions.

II. Introduction

As part of EPA's efforts to enhance th e existing chemicals program under the Toxic Substances Control Act (TSCA) 1 , the Agency identified an ini tial list of widely recognized chemicals, including MDI, for action plan develo pment based on their pres ence in human blood; persistent, bioaccumulative, and toxic (PBT) 2 characteristics; use in consumer products; production volume; and other similar factors. This Action Plan is based on EPA’s initial review of readily available use, exposure, and hazard information 3 on MDI. EPA considered which of the various authorities provided under TSCA and other statutes mi ght be appropriate to address potential concerns with MDI in developing the Action Plan. Th e Action Plan is intended to

describe the courses of action the Agency plans to pursue in the near term to address its concerns and does not constitute a final Agency determin ation or other final Ag ency action. Regulatory proceedings indicated by the Action Plan will in clude appropriate opportunities for public and stakeholder input, including thr ough notice and comment rulemaking pr ocesses. In a concurrent action, a separate Action Plan is under development for Toluene D iisocyanate (TDI), a substance chemically related to MDI with sim ilar hazard and exposure concerns.

1 15 U.S.C §2601 et seq.

2 Information on PBT chemicals can be found on the EPA web site at http://www.epa.gov/pbt/

. 3 Sources initially consulted for basic background informa tion for all the action plan chemicals, including MDI, include Inventory Update Report (IUR) submissions; Toxic Release Inventory (T RI) reporting; data submitted to the HPV Challenge Program; existing hazard and risk assessments performed by domestic and international authorities including but not limited to U.S. Federal government agencies, the Orga nization for Economic Cooperation and Development, the Stockholm Convention on Persistent Organic Pollutants, Health and Environment Canada, the European Union; and others. Details about the specific sources used for th is Action Plan can be found in the

reference list in Section XI. of this document.U.S. Environmental Protection Agency April 2011

2 III. Scope of Review

Diisocyanates (also commonly known as isocya nates) are highly re active and versatile chemicals with widespread commercial and cons umer use. Over 90% of the diisocyanates’ market is dominated by two diisocyanates and th eir related polyisocyanates: MDI and toluene diisocyanate (TDI) (Allport et al. , 2003). They have unique prope rties and functi onal versatility, and contain free isocyanate func tional groups (-N=C=O). When is ocyanates are combined with other compounds that contain free hydroxyl functional groups (i.e. – OH) they react and begin to form polyurethane polymers. This chemical reacti on is completed when all of the initially free – N=C=O groups are bound within the polymer networ k. This process is commonly referred to as “curing.” Products that contain free –N=C=O groups are intended to react and undergo “curing” in the process of use. An example would be an ad hesive, which is sold to be initially applied in an uncured form and as it cures (hardens), bonds two pieces of wood together. Other polyurethane products, such as mattresses, pillows , and bowling balls, are considered completely cured products before they are so ld. Completely cured products are fully reacted and therefore

are considered to be inert and non-toxic (Krone & Kli nger, 2005). This Action Plan focuses on concerns for unreacted uncured products.

Because of their reactivity and the diversity of uses, MDI and its related polyisocyanates (see Appendix 1) are generally supplied by their manufacturers as raw ma terials to formulators who take advantage of the diisocyanates’ chemis try to combine them with other chemicals to create different polyurethanes with a wide diversity of applications. This di versity of applications also means that exposures to diisocyanates can occur in a broad range of production facilities from small workshops to automated production li nes. Diisocyanates are potent dermal and lung sensitizers and a major cause of work-related asthma worldwide (NIOSH , 2006). Diisocyanates are also commonly available in unreacted forms as part of product mixtures widely used in construction, automotive, and other similar applica tions that require an en d-use reaction as part of the functional performance of these products. Such appl ications occurring beyond the confines of a controlled producti on facility could result in ex posures unless there is careful observance of best practices and controls to prevent exposures, in cluding the use of protective equipment, containment, ventilation, proper clean-up practices, and me dical surveillance of anyone who may be exposed.

In the past, consumer exposures have not been a focus of con cern with respect to diisocyanates, because it has been assumed that consumers were generally exposed to products containing cured polyurethanes, which have been generally considered to be inert and non-toxic (Krone & Klinger, 2005). However, an increase in the consumer availability of polyurethane products intended to further react and undergo “c uring” has occurred in the marketplace (see

additional discussion in section on Consumer/General Population Exposure ). For example, installation of spray polyurethane foam insulation in homes, school s and other public buildings is a source of potential exposure to uncured isocyanates by building occ upants, as well as in do-ityourself (DIY) consumer projects. Readily av ailable consumer products, such as adhesives (including glues) and sealants al so contain diisocyanates that are not completely reacted when applied and can provide potenti al exposures (Krone, 2004; Bello et al. , 2007). In addition, certain workers (e.g., self-employed) are not subject to the applicable OSHA exposure limits, and are not legally required to receive health and safety tr aining and chemical hazardU.S. Environmental Protection Agency April 2011

3 information, or wear personal protective equipm ent (PPE) or undergo medical surveillance and therefore could poten tially be overexposed to uncur ed polyurethane products.

EPA is concerned about the pr esence of uncured MDI in products used by or around consumers, as well as other unprotected buildi ng occupants, and the lack of guidance or regulations to protect them. This action plan fo cuses on the potential health effects that may result from exposures to the consumer or self -employed worker while using products containing uncured MDI, or incidental exposures to the ge neral population while such products are used in or around buildings, includi ng homes or schools.

IV. Uses and Substitutes Summary

MDI and TDI are the largest vo lume aromatic diisocyanate s, are high production volume chemicals, and are predominantly used in the production of polyurethanes. In 2008, the U.S. demand for pure MDI was 192.1 million pounds a nd for polymeric MDI was 1,418 million pounds (ACC, 2009). There are many types of pol yurethane products in the marketplace, with foams representing the largest sector of the pol yurethane industry. Non-foam polyurethane use sectors of MDI and polymeric MDI include coatings , adhesives, binders, and sealants. However, these products comprise a small amount of the to tal production volume. Po lyurethane foams take two forms: flexible and rigid. Flexible foam is primarily used for cushioning, while rigid foam is used mainly for insulation. The majority of polyurethane products undergo curing prior to reaching the consumer. However, other polyuretha ne products such as spray foams, coatings, sealants and adhesives may be sold and used, most often in a mixture of formulated product, in an uncured form. Researchers looking at workpl ace exposures to diisocyanates have noted an increase in the number of isocyanate-containing products used by consumers. These researchers also noted that community exposures to isocya nates could potentially result from industrial exposures as well as the use of consumer produc ts containing isocyanate s (Redlich, et al, 2006).

The 2006 Inventory Update Reporting (IUR) data base indicates that MDI chemicals are used in the following consumer/commercial cate gories: adhesives and sealants; paints and coatings; transportation products; rubber and plastic products; and lubricants, greases and fuel additives (EPA, 2010). The vast majority of these products contain forms of MDI as the diisocyanate components. To reduce vapor haza rds, polyisocyanates and pre-polymer forms of isocyanates were developed; however, many pro ducts contain a mixture of MDI monomer and a MDI-based polyisocyanate.

The use of polyurethane foam for insulation is greatly expanding as many federal and

state government programs create incentives for their use in in creasing energy efficiency. In addition to their traditional uses by commercial applicators to insulate roofs and walls of buildings, pour-in-place foam, spray polyurethane foam (SPF) and one-component foam (OCF) have a variety of other uses. Pour-in-place, SPF, and OCF cans are all used in the arts arena for sculpture, mold making, and designing movie and th eater sets. They are similarly used in theme parks, shopping malls, and parade floats (ACC, 2009). In addition, these types of foams are popularly used by arts an d crafts hobbyists.

Other major types of non-foam polyurethane pr oducts sold for use in an uncured form include coatings and adhesives. The terms “coatin gs”, “sealants”, “binders ”, and “adhesives” areU.S. Environmental Protection Agency April 2011

4 sometimes used interchangeably when referri ng to various polyurethane products and some industry sectors use some or all of those four types of products. In particular, the auto refinishing and repair, the marine leisure craft maintenan ce and repair (ACC, 2009), and the floor and deck maintenance and repair (Jarand et al. , 2002; ACC, 2009) sectors ha ve all had a variety of uncured polyurethane products availa ble to both the professional a pplicator as well as the DIY consumer. Additionally, the synthetic recreat ional surfacing industry uses a variety of polyurethane components in formulating its products for both indoor and outdoor surfaces (Advanced Polymer Technology Corporation, 2010). Po lyurethane coatings are available for use by industry and consumers to seal concrete, waterproof walls and refinish floors. Polyurethane sealants have a variety of uses in the automotiv e sector, the largest bei ng glass installation of

windshields and side windows. Polyurethane adhesives are us ed in numerous industrial and consumer applications. Some of these products are specifically marketed to DIY consumers for general multi-purpose applications as well as for specialty uses in woodworking, bookbinding

and other hobbies. Consumer use of adhesives and sealants is a growth sector as noted by an industry overview of this sector in late 2009. This growth re flects increasing numbers of DIY energy-conscious homeowners doing more of their own home renovation and repair work in order to save money, as well as from crafts men and consumers generally continuing to use adhesives (Pianoforte, 2009). The spray foam industry, recognizing the growing use of these products by DIYers, recently developed a webs ite on the use of spray foam with guidance directed specifically to DIYers, in addition to homeowners and professionals (ACC, 2010).

Replacement of diisocyanates in an environm entally and economically friendly manner presents a significant challenge. However, a new class of non-isocyana te polyurethanes that offers potentially safer alternatives to conve ntional polyurethanes has been reported by two research groups (Figovsky & Shapovalov, 2006; Javni et al. , 2008). Other repor ted technologies include an isocyanates-free expanding foam product (Soudal, 2010) a nd a faster curing “isocyanates-free” flexible food packaging adhesi ve that reportedly prevents potential migration of isocyanates into non-dry food. Of note, a soy-based adhesive intended to replace formaldehyde-urea adhesives received a Presid ential Green Chemistry Award (EPA, 2009), but more research is needed to determine if soy-based adhesives would be an adequate substitute for polyurethane adhesives. While research and development of appropriate alternatives is underway with a goal of direct pr oduct substitutions, it is important to focus on the safe use of existing polyurethane products through hazard communication and educating product users.

V. Hazard Identification Summary

The toxicity studies discusse d in this summary were carr ied out on MDI chemicals with unreacted (uncured) isocya nate functional groups.

Environmental and Ecological Hazards . Although there is a moderate acute ecotoxicity profile for MDI, the hazards as sociated with exposures to MDI chemicals have centered on human health effects not ecological effects. E xperimental ecotoxicological data for MDI and its degradation products indicate moderate to low toxicity to aquatic organisms (Bayer, 1992; Bayer, 2000a; Bayer, 2000b; Bayer, 2000c; Bayer, 2009). Other toxicity data suggest low

likelihood of effects to terrestrial biota such as plants and earthworms (Van der Hoeven et al.

, 1992a; Van der Hoeven et al. , 1992b).U.S. Environmental Protection Agency April 2011

5 Toxicity in Humans

. Most of the data on human h ealth hazards resulting from diisocyanate exposures are base d on occupational populations. Thes e data indicate that exposure to diisocyanates can cause contact dermatitis, skin and respiratory tr act irritation, immune sensitization, and asthma (NIOSH, 2006). It is well documented that isocyanate exposure is the leading cause of work-related asthma, and prevalen ce in the exposed workforce is estimated at 1- 20% (Ott et al. , 2003; Bello et al. , 2004). Both inhalation and derm al exposures to diisocyanates are thought to contribute to the develo pment of isocyanate asthma (Bello et al. , 2007; Liljelind et
al. , 2010). Once a worker is sensitized to diisocya nates, subsequent exposu res can trigger severe asthma attacks. Higher incidences of asthma are typically associated with processes that generate higher exposures, such as spray applica tion or heated processes that generate airborne vapors and mists that can expose workers via resp iratory and dermal routes. For example, the UK Health and Safety Executive reported that ve hicle refinishers who sp ray coatings containing isocyanates have an 80 times higher risk of getting asthma compared with the UK working population. (HSE 2009) [http://www.hse.gov.uk/mv r/priorities/isocyanates.htm/]. Fewer cases of diisocyanate asthma have been re ported in work settings with lower isocyanate airborne exposures, and most workers who deve loped diisocyanate asthma have experienced long periods of exposure (months or longer). However, the minimum exposure to isocyanates that can elicit sensitization responses or asth ma is not known. In addition, immune response and subsequent disease in humans can be quite variable (Redlich et al. , 2006). Fatalities linked to diisocyanate exposures in sensitized persons have been reported (NIOSH, 1996; ACC, 2005).

There are very few reports of non-occupationa l exposures to diisocyanates available; however, some incidents have been reported wher e diisocyanates in prod ucts are suspected of causing asthma reactions in humans (Dietemann-Molard et al. , 1991; NIOSH, 1996; Jan et al.

, 2008).

Toxicity in Laboratory Animals

. MDI has low acute toxicity via the oral and dermal routes, but is considered toxic via the inhala tion route in animals (Collins, 2002; ECB, 2005). Dermal absorption of MDI has been experime ntally demonstrated, and MDI is uniformly distributed throughout the body, following inha lation exposure (Collins, 2002; ECB, 2005) (Gledhill et al. , 2005). MDI causes skin, eye, and lung irritation, progressi ve impairment of lung function with long-term inhalation exposure and is a respiratory sensiti zer via both the dermal and inhalation routes of exposure in animals (C ollins, 2002; ECB, 2005). Cross-sensitization has been observed between MDI, TDI, hexamethylen e diisocyanate (HDI) and dicyclohexylmethane diisocyanate (HMDI) in mice, and between MDI, TDI and HDI in humans (O'Brien et al. , 1979). MDI is negative in gene mutation assays in vitro and in chromoso mal aberration assays in vitro

and in vivo (ECB, 2005). Animal data indicate th at MDI may be carcinogenic; however, a consistent association has not been reporte d in epidemiologic studies (IARC, 1987b; IARC, 1987a; ECB, 2005).

VI. Fate Characterization Summary

Hydrolysis is the dominant process in determining the overall environmental fate, transport, and bioaccumulation potential of diisocya nates. Commercially, diisocyanates react at room temperature with other chemicals (i.e. polyols ) to form various polymers. Data shows that water from humidity in air can hydrolyze MDI thus forming the amine, methylene diphenyl diamine/toluene diamine (MDA), which also has h azards associated with it. Although their rapidU.S. Environmental Protection Agency April 2011

6 hydrolysis in surface water will reduce persistence and bioaccumulation in the environment (Yakabe et al. , 1999), under conditions of low humidit y, diisocyanates may be stable long enough to be transported some distances and inhale d. Data from the Toxics Release Inventory shows releases to all media (EPA, 2008b). Despite their apparent rapid reaction time, there is uncertainty regarding diisocyana te vapors and MDA in ambient air as a function of humidity (Dyson & Hermann, 1971). Air releases are of particular concern, because the hydrolysis products formed are irritants and there is a potential for inhalation exposure.

VII. Exposure Characterization Summary

Occupational Exposure. Approximately 280,000 U.S. workers were estimated to be potentially exposed to diisoc yanates in 1996 (NIOSH, 1996) but given industry growth and new applications (Bello et al. , 2007), this estimate is expected to be higher today. OSHA regulates workplace exposures to MDI through its permissi ble exposure limits (PELs) (see Appendix 2). To reduce worker exposures when exposure levels exceed its PELs, OSHA requires use of PPE when engineering controls (e.g., ve ntilation) or administrative contro ls are infeasible or fail to reduce levels adequately.

Airborne MDI concentrations during manufact uring processes are influenced by whether the material is heated or spraye d, how the diisocyanate is reacted or cured, whether the process is conducted in an open or closed system, and the types of sampling methods used (Booth et al.

, 2009). Exposures to MDI during SPF insulation and binder, coating, adhesive and sealant operations were found to be greater than MDI ex posures from the production of other types of polyurethane products (e.g, mattr esses) which reach consumers in a cured form (Booth et al.

, 2009). Notably high MDI airbor ne exposures have been documented among workers during spray-on applications of truck bed liners and rigid foams for insulation (SPF) (Crespo & Galan, 1999; Lofgren et al. , 2003; Bonauto et al. , 2005; NIOSH, 2006; Lesage et al. , 2007). Certain

NIOSH and OSHA evaluations ha ve shown that worker exposu res levels can be above OSHA PELs when spray applying MDI (NIOSH, 2004; Fairfax & Brooks, 2006) Airborne

concentrations of MDI can also occur above estab lished exposure limits in pour-in-place applications during process upsets (Booth et al. , 2009).

Occupational skin exposures in workers exposed to MDI are of concern because isocyanate sensitization and/or asthma has occurred in cases where the potential for skin exposure is substantial but measured airborne MDI monomer levels are below Occupational Exposure Levels (OELs) or below the limits of det ection with the methods used, or where similar MDI levels would be expected but MDI air monitoring data is not available (Bernstein et al.

, 1993; Ulvestad et al. , 1999; Petsonk et al. , 2000; Sommer et al. , 2000; Donnelly et al. , 2003). Skin exposure to MDI at work can occur even with use of personal protective equipment (Bello

et al. , 2004).

In 132 OSHA inspections conducted be tween February 2004 and March 2005, approximately 46% of MDI samples collected duri ng MDI-based spray-on urethane use in truckbed lining exceeded OSHA’s PEL (Fairfax & Brooks, 2006). The truck bed lining industry is primarily composed of small employers (six or fewer workers) with an estimated total of 10,000 workers (Lofgren et al. , 2003; Fairfax & Brooks, 2006). Sinc e polyurethane coatings and

sealants are marketed and used for truck tra ilers, house decks, walls, foundations and sportsU.S. Environmental Protection Agency April 2011

7 flooring and these applications use the same or similar chemicals, spray techniques, and equipment as the spray-on truck bed lining pr ocess and SPF insulation, excessive exposure to MDI may occur during these related applications, resulting in risk to spray gun users and other nearby workers (NIOSH, 2006). However, non- OSHA covered self-employed workers and small firms, may not have access to or be aware of the hazard information and appropriate precautions to take when using uncured polyur ethane products (Krone, 2004). Also, nonoccupational exposures of workers, self-employed or otherwise, that have been sensitized to diisocyanates at work deserv e special attention (ECB, 2005).

EPA is aware that there is uncertainty about curing time of various products under

different situations and that addi tional data are needed to addre ss certain concerns , such as reentry time, which are important for impr oving communication to prevent exposure. Additionally, while OSHA and NIOSH have develope d methods to estimate air concentrations within workplaces, current methods underestimate ai r concentrations and may warrant the use of a compensation factor and/or development of improved analytical methods. Methods for detection of dermal exposure are in the early stages of developm ent and will be key to estimating dermal exposures. There are several data gaps associated with dermal exposure, sensitization, and the availability of uncured isocyanate groups (Streicher et al. , 1998; Bello et al. , 2007). In the U.S., only isocyanate monomers (e.g., TDI and MDI) are regulated, although similar polyisocyanates that are widely used in commercial and cons umer products contain the same reactive isocyanates. EPA is concerned that th ere does not appear to be sufficient recognition that potential exposures of c onsumers and non-OSHA regulated workers to MDI and its related polyisocyanates may need to be addressed with similar recommendations for use of engineering controls, PPE, and hazard communication as those required for OSHA-regulated occupational settings.

Consumer/General Population Exposure. The higher exposure operations identified in occupational settings (Booth et al. , 2009) use polyurethane produc ts which are most commonly used by consumers (e.g., spray foam, adhesives). Thus, consumers, bystanders, building occupants (including children), hobbyists and DIY applicators may be exposed to uncured MDI when using similar products. Unlike workers w ho are protected by workpl ace regulations and, in most cases, have access to hazard information and training for working with diisocyanates, most consumers are unaware of the potential hazards of consumer products containing uncured MDI. Consequently, incorrect use because of insuffi cient and inadequate hazard communication may lead to increased consumer exposure. Even if consumers are aware of the hazards, they may not take appropriate precautions. The European Union assumed that “the systematic use of PPE by the consumer will be unlikely.” (ECB, 2005). C oncerns for potential consumer exposure to MDI-containing products ultimately resulted in a regulation requiri ng the inclusion of appropriate gloves and precautionary statemen ts in consumer products containing MDI (European Union, 2009).

Consumer use of uncured polyurethane products that contain MDI ha s increased rapidly as the market for consumer products has expanded (Krone, 2004; Redlich et al. , 2006). In 2004,

the National Institutes of Health Household Pr oducts database, which represents a random sampling of brand name products, listed 16 produ cts containing MDI (Krone, 2004). In 2010, a

search of the same database resulted in 43 products containing MDI (NIH, 2010). In addition, there is a growing availability of products, both consumer products and those labeled asU.S. Environmental Protection Agency April 2011

8 “professional grade,” that contain uncured MDI in retail and home improvement stores, as well as for purchase over the Internet that are available to the co nsumer (MPK Enterprises, 2010; NIH, 2010 ). Some professional art organizatio ns have noted the common use of uncured polyurethane products by their members and wa rn their members of the potential hazards associated with these products in their safety library (United Scenic Artists, 2010). However, it is unclear whether amateur and school arts group s are similarly aware of the potential hazards resulting from the use of these same products.

Rigid foam products containing MDI are predominantly used to make spray foam insulation by a variety of systems. Exposures to consumers are not well characterized. The exposure potential varies with the method and quan tity used, particle size distribution, and endproduct curing time. With two-component high pressure spray polyurethane foam systems, chemical migration between floors was noted with certain conditions. Area samples show that occupants and bystanders, including sensitive populations, may be exposed at levels above the workplace exposure limits (Crespo & Galan, 1999; Lesage et al. , 2007; Bayer, 2009; IRSST, 2009). This is of special concer n because exposure limits for the general population’s exposure to hazardous chemicals are lower than workplace exposure limits, primarily because the general population also includes the sick, the disable d, sensitive and immuno-compromised individuals, and children (Redlich, et al , 2006). Several researchers have recommended establishing a work zone to minimize exposure of unprotected individua ls during application. This is supported by data that show reduction of MDI (Lesage et al. , 2007) concentration w ith distance from the application site (Lesage et al. , 2007). Until polyurethane products fully cure, there may be the potential for inhalation and dermal exposure. However, limited information on the impact of such factors as product composition, temperature, humidity, and application technique on curing

times affects determination of safe re-entry time after application.

Children exposed to the same airborne concentrations of MDI as adults may receive a larger dose because they breathe more per poun d body weight and per unit respiratory surface area. Additionally, children may be more highl y exposed to environmental toxicants through

dermal routes than adults. For instance, children may crawl, roll or sit on surfaces treated with chemicals (i.e., carpets and floors) and play with objects such as toys where residues may settle. Similarly, children have a higher surface area rela tive to body weight, which would result in a greater dose relative to body weight for a child than for an adult with equivalent skin exposure (EPA, 2008a), and children are more likely to cr awl, lay, or spend time on the floor. Children may have a greater potential for expo sure if they use or are bysta nders to the use of uncured MDI products, because they may not have fully developed judgment for following labeling instructions and safety precautions and may not cease activity even when they are experiencing symptoms of exposure. An accidental acute expo sure of children to high levels of MDI in a polyurethane sealant used on a school athletic tr ack was associated with asthma-like symptoms, including among children with no prior hi story of respiratory dysfunction (Jan et al. , 2008). This observation is consistent with MDI being a well known source of occupational asthma. Children with asthma are an especially vulnerable populati on for exposure; they are more susceptible to inflammatory narrowing of the airways, which re sults in a proportionally greater obstruction of their smaller respiratory system (NIH , 2011; Trasande & Thurston, 2005).

In contrast to the large amount of exposure data available for professional workers who work with diisocyanates, there is limited e xposure data available ch aracterizing the use andU.S. Environmental Protection Agency April 2011

9 exposure scenarios of consumer and commercial products containing uncu red MDI. Additional data characterizing the concentratio n of MDI in the air is needed. It is unknown to what extent factors such as application techniques, product composition, and me thod of measurement influence the availability of uncured MDI. In addition, comparing conc entrations to existing workplace exposure limits is not appropriate because the worker PEL is not sufficiently protective for the consumer (Redlich, et al , 2006).

IX. Risk Management Considerations

Similar quantities of uncure d products are available for pur chase by either professionals

or consumers. Numerous authors have noted the versatility of polyur ethane as well as its increasing uses. EPA is concerned that the pote ntial exists for similar exposures in non-OSHAregulated situations. Both primary users and bys tanders should be made aware of the potential risks and appropriate precautions to take when un cured MDI is being used. In addition, personal and health care products, such as bandages a nd orthopedic casts could contain uncured MDI but are beyond the scope of this action plan. Howeve r, exposures from use of such products could

contribute to cumulative diis ocyanate exposures (Sommer et al. , 2000; Donnelly et al. , 2003). The factors described above suggest that a heightened concern for potential risks of diisocyanate exposure to children should be addressed duri ng actions taken to manage these chemicals.

Current and Ongoing Regulatory and Related Activities

MDI and its related polyisocyanates are the su bjects of a variety of regulatory and related activities, some of which are summarized below. Additional details, incl uding numerical values, are provided in Appendix 2.

EPA Regulatory Activities . MDI is regulated under the Clean Air Act as a hazardous air pollutant and under RCRA and CERCLA as a h azardous waste. Diisocyanates as a category are subject to Toxics Release Inventory reporti ng. Under TSCA, EPA ha s previously used its authority under TSCA sections 8(a) and 8(d) to request information fr om industry (see 40 CFR parts 712 and 716). EPA has also received subm issions regarding diisocyanates under TSCA section 8(c) and TSCA secti on 8(e). Diisocyanates are a TSCA New Chemicals Program Chemical Category and any new ch emical substance falling in th at category may be further regulated after a TSCA section 5 premanufacture notice has been submitted (EPA, 2002).

Spray Polyurethane Foam (SPF) Federal Partnership Promoting Stewardship &

Research . In 2009, EPA convened a multi-agency partnership with OSHA, NIOSH, and the Consumer Product Safety Commission (CPSC) to ev aluate and address potential exposures to isocyanates and other chemicals during installation of spray polyur ethane foam (SPF) insulation

and air sealants in homes and schools. Commer cial and DIY applicators, as well as building occupants are often unaware of inhalation and dermal hazards. Applicators and others at the work site may not wear adequate PPE. Buildi ng occupants, who remain on the premises during the operations or re-enter the site before the pr oduct is fully cured may be at risk. The federal agencies are working with the polyurethan es industry to ensure accessible hazard communication, applicator trai ning, and best workplace practic es to prevent exposure to isocyanates and other SPF chemicals. In addi tion, the federal group has identified critical research needs to assess and measure exposures to total reactive isocyanate groups (TRIG)U.S. Environmental Protection Agency April 2011

10 during use and curing of SPF products. EPA will con tinue to work with its federal partners, the polyurethanes industry, and others to ensure improved labeling a nd product safety information for polyurethane products containing unreacted is ocyanates, especially products targeted to consumers. EPA is also considering a green ch emistry challenge to encourage the development

of safer alternative chemicals.

European Union . Following publication of an MDI risk assessment which identified risks to human health for consumers, the Eur opean Union (EU) amended its REACH regulation

to include restrictions on certain consumer uses of MDI. Effective December 27, 2010, all consumer products manufactured and imported in to the EU containing concentrations of 0.1 percent or more MDI must include specific type s of protective gloves a nd specific warnings and use instructions (European Union, 2009).

X. Next Steps

In conducting this review, EPA considered a number of potentia l actions, including regulatory actions under TSCA sections 4, 5, 6, and 8; cooperative actions with other federal agencies; and voluntary actions as described above. Based on EP A’s screening level review of MDI and its related polyisocyanates (Appendix 1), EPA intends to:

1. Issue a data call-in for uncured MDI under TS CA section 8(c) to determine if there are allegations of significant adverse effects and in itiate a TSCA section 8(d) rulemaking for onetime reporting of relevant unpublished health and safety studies for uncured MDI.

2. Consider initiating a TSCA section 4 test rule to require exposure monitoring studies on uncured MDI and its related polyisocyanates in consumer products and exposure monitoring studies in representative locati ons where commercial products w ith uncured MDI and its related polyisocyanates would be used.

3. Consider initiating rulemaki ng under TSCA section 6 for a. Consumer products containing uncured MDI, and b. Commercial uses of uncured MDI pr oducts in locations where the general population could be exposed.

4. Consider identifying additional diisocyana tes and their related polyisocyanates that may be present in an uncured form in consumer products that should be evaluated for regulatory and/or voluntary action.

XI. References

ACC (2005). American Chemistry Council. TSCA 8(e) Notice of Substantial Risk 8EHQ-0905- 16225 Fatalities linked to diisocyanates. EPA. ACC (2009). American Chemistry Council. 2008 E nd Use Market Survey on the Polyurethanes Industry in the US, Canada, and Mexico. (A. IAL Consultants, Ed.) Note: this is a proprietary document. ACC (2010). American Chemistry Council. Spra y Polyurethane Foam Health and Safety. March 3, 2011. http://spraypolyurethane.org/.U.S. Environmental Protection Agency April 2011

11 Advanced Polymer Technology Corporation (2010). Advanced Polymer Technology Corporation July 6 2010. h ttp://www.advpolytech.com/index.htm

. Allport, D., Gilbert, D., and Outterside, S. (2003). MDI and TDI: Safety, Health and the

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Appendix 1

Tier 1: MDI monomers and related isomers and polymers

No CASRN CA Index Name Acronym Common Name

1 101-68-8 Benzene, 1,1'-methylenebis[4- isocyanato- 4,4’-MDI 4,4’-Methylenediphenyl diisocyante

2 5873-54-1 Benzene, 1-isocyanato-2-[(4- isocyanatophenyl)methyl]- 2,4’-MDI 2,4’-Methylenediphenyl diisocyante

3 2536-05-2 Benzene, 1,1'-methylenebis[2- isocyanato- 2,2’-MDI 2,2’- Methylenediphenyl diisocyante

4 26447-40-5 Benzene, 1,1'- methylenebis[isocyanato- MDI Methylenebis(phenyl isocyanate)

5 9016-87-9 Isocyanic acid, polymethylenepolyphenylene ester Polymeric

MDI Poly(Methylenebis(phe nyl isocyanate)

Tier 2: MDI dimers, trimers and polymers

No CASRN CA Index Name Acronym Common Name

6 17589-24-1 1,3-Diazetidine-2,4-dione, 1,3- bis[4-[(4-isocyanatophenyl) methyl]phenyl]- 4,4’-MDI

dimer 4,4’-Methylenediphenyl diisocyante dimer

7 31107-36-5 1,3-Diazetidin-2-one, 1,3-bis[4-[(4- isocyanatophenyl)methyl]phenyl]-4- [[4-[(4-isocyanatophenyl)methyl] phenyl]imino]- 4,4’-MDI

trimer 4,4’-Methylene diphenyl diisocyante

trimer (or Uretonimine of 4,4’- MDI)

8 25686-28-6 Benzene, 1,1'-methylenebis[4- isocyanato-, homopolymer 4,4’-MDI

homopolymer 4,4’-Diphenyl methanediisocyanate homopolymer

Appendix 2 – Regulatory and Exposure Limits for MDI

EPA . The EPA’s Integrated Risk Informati on System (IRIS) program has developed a

reference concentration (RfC) for MDI of 6 x 10 -4 mg/m 3 using histopathologi cal changes in the upper respiratory system in animals as the critical effect (EPA, 1998).U.S. Environmental Protection Agency April 2011

15 OSHA . Diisocyanate hazards are addressed by OSHA in specific standards for the general industry, shipyard employment, and the construction industr y, including PELs for workplace exposure.

OSHA’s PEL for the MDI monomer is 0.2 mg/m 3 (0.02 ppm) as a ceiling limit (29 CFR § 1910.1000). OSHA also requires the use of PPE to reduce worker exposure to hazards when engineering and administrative controls are not f easible or effective in reducing exposure below

its PELs.

NIOSH

. In 1996 and 2006, NIOSH issued Alerts to prevent asthma and death from diisocyanate exposure to workers in certain situations (NIOSH, 1996; NIOSH, 2006). NIOSH considers SPF insulation application to presen t hazards similar to other spray polyurethane applications and recommends use of the same safety procedures and PPE.

NIOSH’s Recommended Exposure Limit (R EL) for the MDI monomer is a Time Weighted Average (TWA) of 0.05 mg/m 3 (0.005 ppm) for up to a 10-hour workday during a 40- hour workweek with a ceiling limit of 0.2 mg/m 3 (0.02 ppm) for any 10-minute period (NIOSH, 2005). The NIOSH REL is intended to prevent acute and chronic irritation and sensitization of workers but not to prevent health effects in workers who are already sensitized. Per NIOSH,

available data do not indicate a c oncentration at which MDI fails to produce adverse reactions in sensitized persons (NIOSH, 2006).

ACGIH . American Conference of Governmental Industrial Hygienists. Threshold Limit Values (TLVs) for MDI address respiratory sens itivity but not dermal sensitivity. It has been suggested that there is now sufficient informati on to recommend the addition of a “skin notation” to the TLVs for MDI to bring attention to the potential for absorption of diisocyanates through

the skin.

ACGIH has assigned the MDI monomer a TLV of 0.05 mg/m 3 (0.005 ppm) as a TimeWeighted Average (TWA) for a normal 8-hour workday and a 40-hour workweek. The ACGIH TLV for MDI is based, among other things, upon th e potential for sensit ization and meant to protect workers from induction of this effect (ACGIH, 2009).

California, OEHHA . In April 2010, California’s O ffice of Environmental Health Hazard Assessment (OEHHA) released “for co mment” draft documents describing proposed Reference Exposure Levels (RELs) for MDI which ha ve been revised to in clude consideration of possible differential effects on the health of infa nts, children and other sensitive subpopulations (California EPA, 2010).

EU . Following publication of an MDI risk asse ssment which identified risks to human health for consumers, the EU amended its REACH regulation to include restrictions on certain

consumer uses of MDI. Effective Decembe r 27, 2010, all consumer products manufactured and imported into the EU containing concentrations of 0.1 percent or more MDI must include specific types of protective glove s and specific warnings and use instructions (European Union, 2009).