U.S. Environmental Protection Agency April 2011

Toluene Diisocyanate (TDI)

And Related Compounds
Action Plan [RIN 2070-ZA14]

I. Overview

This Action Plan addresses the use of toluen e diisocyanate (TDI) and related compounds (See Appendix 1) in products that may result in consumer and general population exposures, particularly in or around buildings, including ho mes and schools. Diisocyanates are well known dermal and inhalation sensitizers in the workplac e and have been documented to cause asthma, lung damage, and in severe cases, fatal reacti ons. This Action Plan focuses on the potential health effects that may result from exposures to the consumer or self-employed worker while using products containing uncured (unreacted) diisocyanates (e .g., spray applied sealants and coatings) or incidental exposures to the general population while such products are used in or around buildings, including homes or schools. In conducting this review of TDI compounds, EPA considered a number of potential actions, in cluding 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 TDI, for action plan deve lopment based on their presence 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 TDI. EPA considered which of the various authorities provided under TSCA and othe r statutes might be a ppropriate to address potential concerns with TDI in developing the Action Plan. The 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 deve lopment for Methylene Diphenyl Diisocyanate (MDI), a substance chemically related to TDI with similar 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 information for all the action plan chemicals, including TDI, 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.

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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 their related polyisocyanates: MDI and TDI (Allport et al. , 2003). They have unique properties and functional versatility, and contain free isocyanate functional groups (-N=C =O). When isocyanates are combined with other compounds that contain free hydroxyl functiona l groups (i.e. –OH) they react and begin to form polyurethane polymers. This chemical reaction is completed when all of the initially free –N=C=O groups are bound within the polymer network. 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 adhesive, which is sold to be initially applied in an uncured form and as it cures (hardens), bonds two pieces of w ood together. Other polyurethane products, such as mattresses, pillows, and bowling balls, are cons idered completely cured products before they are sold. Completely cured products are fully re acted and therefore are co nsidered to be inert and non-toxic (Krone & Klinger, 2005). This Action Plan focuses on concerns for unreacted, uncured products.

Because of their reactivity and the diversity of uses, TDI 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 di versity of applications . This diversity of applications also means that exposures to diis ocyanates can occur in a broad range of production facilities from small workshops to automated pr oduction lines. Diisocyanates are potent dermal and lung sensitizers and a major cause of work-re lated asthma worldwide (NIOSH, 2006). Diisocyanates are also commonly available in unreacted forms as part of product mixtures widely used in construction, automotive, and othe r similar applications th at require an end-use reaction as part of the functional performance of these products. Such applications occurring beyond the confines of a controlled production facil ity could result in expo sures unless there is careful observance of best prac tices and controls to prevent exposures, including the use of protective equipment, containment, ventil ation, proper clean-up pr actices, and medical 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 or exposure to polyurethane products intended to further react and undergo “cu ring” has occurred in the marketplace (see additional discussion in section on Consumer/General Population Exposure ). For example, consumer products, such as adhesi ves sealants may contain TDI compounds that are not completely reacted when applied and can provide potential exposures both to the consumer as the direct user or as a bystande r to such product use by others (Krone, 2004; Bello
et al. , 2007). In addition, certain wo rkers (e.g., self-employed) are not subject to the applicable OSHA exposure limits, and are not legally require d to receive health and safety training and chemical hazard information, or wear personal protective equipment (PPE ) and therefore could potentially be overexposed to unc ured polyurethane products.

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EPA is concerned about the pr esence of uncured TDI 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. Therefore, this Ac tion Plan focuses on potenti al health effects that may result from exposures to the consumer or self-employed worker when such a person uses products containing uncured TDI, or incidental exposures to the general population when such products are used in or around buildi ngs, including 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 TDI was 425.2 million pounds (ACC, 2009). There are many types of polyurethane products in the marketplace, with foams repres enting the largest sector of the polyurethane industry. Non-foam polyurethane us e sectors of TDI include coati ngs, adhesives, binders, and sealants. However, these products comprise a small amount of the total production volume. Polyurethane foams take two forms: flexible a nd rigid. Flexible foam is primarily used for cushioning, while rigid foam is used mainly for insulation. TDI chemicals are primarily used in the production of flexible foams. The majority of polyurethane products undergo curing prior to reaching the consumer. However, other polyuretha ne products such as coatings, sealants and adhesives may be sold and used, most often in a mixture of formulated product, in an uncured form. Researchers looking at workplace 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 isocyanate s could potentially result from i ndustrial exposures as well as the use of consumer products containing isoc yanates (Redlich, et al, 2006).

Because of its hazards, industry claims that uncured TDI is used in products intended for industrial use only (DOW, 2009). Generally, MD I and aliphatic diisocyanates have been replacing TDI in coating and adhesive products (Ott et al. , 2003). The 2006 Inventory Update Reporting (IUR) database indicates that TDI chemicals are used in the following consumer/commercial categories: adhesives and sealants; paints and coatings; transportation products; rubber and plastic products; wood and w ood furniture; and electrical and electronic products (EPA, 2010). The Household Products Database currently li sts one uncured TDI product, a concrete sealant for fl oors (NIH, 2010 ). That product and the deck coating used in an exposure study (Jarand et al. , 2002) are still available for purchas e and it is not clear that the products are limited to professional use only. Ba sed on online research, it appears that floor coatings and sealants are the primary types of products containing uncured TDI which might be
available to consumers.

Additionally, the synthetic recr eational surfacing industry uses a variety of polyurethane components in formulating its products for both i ndoor and outdoor surfaces (see for example, Dow, 2011). Polyurethane coatings are availa ble for professional use to seal concrete, waterproof walls and refinish fl oors. So-called “for profession al use” products may also be available for purchase and use by consumers or coul d be used in the presence of consumers. Polyurethane sealants have a va riety of uses in the automotive sector, the largest being glass
installation of windshields and side windows. Consumer use of adhesives and sealants is a potential growth sector as noted by an industry overview of this sector in late 2009. This growth

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reflects increasing numbers of DIY energy-cons cious homeowners doing more of their own home renovation and repair work in order to save money, as well as from craftsmen and consumers generally continuing to use adhesive s (Pianoforte, 2009). The spray foam industry, recognizing the growing use of these products by DIYers, recently developed a website 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 conventional polyurethanes has been reported by two research groups (Figovsky & Shapovalov, 2006; Javni et al. , 2008). Other reported 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 Presidential 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

Environmental and Ecological Hazards

. Because of their low ecotoxicity profiles, the hazards associated with exposur es to TDI chemicals have centered on human health effects not ecological effects. Experiment al ecotoxicological data for TD I and its degradation products
indicate moderate to low toxici ty to aquatic organisms (Curtis et al. , 1978; MITI, 1992;
Tadokora et al. , 1997; Pedersen et al. , 1998). Other toxicity data suggest low likelihood of effects to terrestrial biota such as plants, earthworms (Van der Hoeven et al. , 1992a; Van der

Hoeven et al. , 1992b), and birds exposed to 2,4-TDI and 2,6-TDI (IUCLID, 2000).

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). Both inhalation and dermal exposures to diisocyanates are thought to contribute to the development of isoc yanate asthma (Bello et al., 2007). It is well documented that isocyanate exposure is the l eading cause of work-related asthma, and prevalence in the exposed workforce is estimated at 1-20% (Ott et al. , 2003; Bello et al. , 2004). 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/mvr/priorities/isocyanates.htm/]. Fewer cases of diisocyanate asthma have been reported in work settings with lower isocyanate airborne exposures, and most workers who de velop diisocyanate asthma have experienced long periods of

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exposure (months or longer). However, the mi nimum exposure to isocyanates that can elicit sensitization responses or asthma 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 re ported (NIOSH, 1996; ACC, 2005). The EPA IRIS program has developed a reference concentra tion based on occupational exposure data (see Appendix 2)

There are very few reports of non-occupatio nal exposures to TDI available; however, there are case reports suggesting that paraoccupa tional asthma may have resulted from incidental exposure to TDI (De Zotti et al. , 2000). In addition, antibodies to TDI have been detected in some residents living near a facility that ma nufactured polyurethane foam, indicating that exposures may be occurring from environmental re leases from the plant and sensitizing some individuals (Orloff et al. , 1998; Darcey, 2002).

Toxicity in Laboratory Animals

. In acute, subacute, and chronic animal exposure studies, the respiratory tract was the target organ, with nasal irritation evident at concentrations above 0.1 ppm and effects becoming more severe with increasing concentration. (Collins, 2002; ECB, 2005). TDI is uniformly distributed th roughout the body, following inhalation exposure (Collins, 2002; Gledhill et al. , 2005). TDI causes skin, eye, and lung irritation, progressive impairment of lung function with long-term inha lation exposure and is a respiratory sensitizer
via both the dermal and inhalation routes ofexposure in animals (Collins, 2002). Crosssensitization has been observed between MDI, TDI, hexame thylene diisocyanate(HDI) and dicyclohexylmethane diisocyanate (HMDI) in mi ce, and between MDI, TDI and HDI in humans (O'Brien et al. , 1979). TDI is positive in gene mutation assays in vitro and negative in an in vivo mouse micronucleus assay (Collins, 2002).

Animal data indicate that TDI may be car cinogenic (Collins, 2002). Data from recent
studies of animals show that cancer is associat ed with exposure to commercial-grade TDI (an

80:20 mixture of 2,4- and 2,6-TDI). The responses of both rats and mice tr eated with TDI meet the OSHA criteria for classifying a substance as a potential occupa tional carcinogen (29 CFR 1990.112). NIOSH therefore recommends that occupa tional exposure to TDI and its isomers be minimized (NIOSH 1989).

The carcinogenic effects of TDI (Loeser 1983; NTP 1986) were also investigated by the International Agency for Research on Cancer (IARC) and the World Health Organization (WHO) (IARC 1986; WHO 1987). IARC concluded that data were sufficient to show that TDI
causes cancer in animals. WHO concluded that TDI should be treated as a potential human carcinogen. In addition, NIEH S has listed TDI in its 11 th Report on Carcinogens as reasonably anticipated to be carci nogenic to humans.

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 TDI th us forming the amine, toluene diamine (TDA),

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which also has hazards associated with it. Al though their rapid hydrolysis in surface water will reduce persistence and bioaccumulation in the environment (Yakabe et al. , 1999), under conditions of low humidity, diisocyanates may be stable long enough to be transported some
distances and inhaled. Data fr om the Toxics Release Inventor y shows releases to all media (EPA, 2008b). Despite their apparent rapid reac tion time, there is unc ertainty regarding diisocyanate vapors and TDA 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 diisocyanates 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 TDI 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.

There is a potential for workplace exposure to TDI in all industrial, commercial, or manufacturing settings where TDI is present (DOW, 2009). Because of the high volatility of TDI, exposure can occur in all phases of its manufacture and use (NTP, 2005). Short-term
airborne concentrations that exceed OSHA’s cei ling PEL for TDI continue to be reported in polyurethane foam produc tion facilities (Ott et al. , 2003), especially during upset conditions, within the foam line tunnel, or in close contact with fresh cut buns (Cummings & Booth, 2002). Overexposures to TDI were documented for floor finishing in both person al and area samples in one NIOSH evaluation (NIOSH, 2004) . In another NIOSH evaluation of flexible polyurethane foam workers, although airborne exposures to TDI were below recommended exposure limits, respiratory (TDI-induced bronchitis and asthma), mucous membrane, and skin problems were noted for workers and these symptoms were associ ated with indicators of TDI exposure (NIOSH, 1998). Some sensitized workers susceptible to developing occupa tional asthma could react to isocyanate monomers at concen trations that are below 1% of the 8-hour threshold limit value (TLV) of 5 ppb for TDI/MDI (Gagne et al. , 2005). For TDI, NIOSH recommends exposure reduction to the lowest feasible minimum (NIO SH, 2005) and ACGIH is looking at reducing its 2011 TLVs for 2,4- and 2,6-toluene diisocyanate from current limits through a Notice of Intended Change (NIC). See A ppendix 2 for numerical values.

Self-employed workers and small firms may not have access to or be aware of the hazard information and appropriate precautions to ta ke when using uncured polyurethane products (Krone, 2004). Investigators observed workers applying a TDI-containing moisture cure urethane (MCU) floor finish w ithout using any respiratory prot ection in one investigation of airborne exposures during residential a pplication of the MCU product (ATSDR, 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 re

entry time, which are important for impr oving communication to prevent exposure.

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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 development. There are several data gaps associated with dermal exposure, sensitization, an d the availability of unc ured 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 wide ly used in commercial and consumer products contain the same reactive isocya nates. EPA is concerned that there does not appear to be sufficient recognition that potential exposures of consumers and non-OSHA regulated workers to MDI, TDI and their related polyisocyanates may need to be addressed with similar recommendations for use of engineeri ng controls, PPE, and hazard communication as those required for OSHA-regul ated occupational settings.

Consumer/General Population Exposure. Consumers, bystanders, building occupants (including children), hobbyists a nd DIY applicators may be exposed to uncured TDI in some products. Little information is available to document consumer use of products containing uncured TDI. It appears that over the years, MDI has been substituted for TDI in some consumer products (ACC, 2009). Although an indus try product safety assessment states that uncured TDI products are intended for industr ial use only (Dow, 2009), many such products are
available on the Internet from fo rmulators and distributors furthe r down the supply chain and it is not clear if there is any contro l over who purchases them. Un like workers who are protected by workplace regulations and, in most cases, have access to hazard information and training for working with diisocyanates, it is likely that mo st consumers are unaware of the potential hazards of consumer products containing uncured TDI. Consequently, incorrect use because of insufficient and inadequate haza rd communication may lead to in creased consumer exposure.
Even if consumers are aware of the hazards, they may not take appropriate precautions.

While there is not much information availa ble about direct consumer use, numerous bystander exposures to TDI products have been f ound in the literature, in cluding: emissions of TDI from concrete patio sealants (Kelly et al. , 1999; Jarand et al. , 2002); and detection of TDI in building air samples following use of urethane s containing TDI to coat wood floors (NYC

DOHMH, 2010). In addition, two cases of pa raoccupational TDI asthma were documented through specific inhalation challe nges after the indivi duals were exposed to uncured TDI (De
Zotti et al. , 2000).

Children exposed to the same levels of TDI vapor as adul ts may receive a larger dose because they have greater lung surface area :body weight ratios and increased minute volumes:weight ratios. TDI vapor is heavier than air and may layer close to the floor. Children who crawl, roll or sit on surfaces treated with chemicals (i.e., carpe ts and floors) and play with objects such as toys where residues may settle may receive higher doses of inhaled toxicants than adults present in the same room (ATSDR, 2002). Because of their re latively larger surface area:body weight ratio, children ar e more vulnerable to toxicant s absorbed through the skin. Children may have a greater potential for exposure if they use or are bys tanders to the use of uncured TDI 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. Additiona lly, chronic exposure may be more serious for

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children because of their potenti al longer latency period, as they have more opportunity for both exposure to and expressions of harmful effects from exposure to substances such as TDI (ATSDR, 2001; ATSDR, 2002, EPA, 2008a ). Children with asthma are an especially vulnerable population for exposure; they are more susceptible to inflammatory narrowing of the airways, which results in a proportionally greater obstruction of their sm aller 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 exposure data available ch aracterizing the use and exposure scenarios of consumer and commercial products containing uncu red TDI. Additional data characterizing the concentration of TDI in th e 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 TDI. 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 types of uncured products are availa ble for purchase by either professionals or
consumers. Numerous authors ha ve noted the versatility of polyur ethane as well as its increasing uses. EPA is concerned that the potential exis ts for similar exposures in non-OSHA-regulated situations. Both primary users and bystanders should be made aware of the potential risks and appropriate precautions to take when uncured TDI is being used. It is unclear how many products containing uncured TDI are available fo r consumer purchase. However, even if uncured TDI products are being used by professionals , they could be used in locations, such as surfacing running tracks and gymnasium floors, where unintended exposure of bystanders, especially children, could be a concern. It is important to determine whether there are uncured TDI products being used in ways that could pr esent potential exposure concerns. In addition, some personal and health care products could c ontain uncured diisocyanates but are beyond the scope of this action plan. However, exposures from use of such products could contribute to cumulative diisocyanate exposures (Sommer et al. , 2000; Donnelly et al. , 2003). The factors described above suggest that a he ightened concern for potential ri sks of diisocyanate exposure to children should be addressed during actio ns taken to manage these chemicals.

Current and Ongoing Regulatory and Related Activities

TDI 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 . TDI is regulated under the Clean Air Act as a hazardous air pollutant and under RCRA and CERCLA as a hazardous waste. Diisocyanate s as a category and TDI individually are subject to Toxics Release Inventory re porting. Under TSCA, EPA has previously used its authority under TSCA secti ons 8(a) and 8(d) to request information from industry (see 40 CFR parts 712 and 716). EPA has also received submissions regarding diisocyanates under TSCA section 8(c) and TSCA section 8(e). Diisocyanates are a TSCA New

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Chemicals Program Chemical Category and any ne w chemical substance falling in that category may be further regulated after a TSCA sec tion 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) 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.

Canada . On May 12, 2010, Canada added TDI to its List of Toxic Substances following
an assessment which determined that TDI is car cinogenic and affects the respiratory system. Environment Canada published a proposed P2 Pollution Prevention Planning Notice for the polyurethane and other foam sector. A propos ed action to investigate non-foam consumer products containing TDIs under the Hazard Prod ucts Act is in development (Environment Canada, 2010).

IARC . The International Agency for Research on Cancer (IARC) has classified TDI as possibly carcinogenic to humans (IARC, 1987b).

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 TDI and its related polyisocyanates (Appendix 1), EPA intends to:

1. (A) Initiate rulemaking under TSCA secti on 5(a)(2) for a Significant New Use Rule (SNUR), designating the use of uncured TDI an d its related polyisocyan ates in a consumer product as a new use. As indicated in S ection IV, Uses and Substitutes Summary, some members of the industry have stated that unc ured TDI is not used in consumer products.

(B) If, however, public comments on the propos ed SNUR indicate that there are ongoing uses of uncured TDI in consumer products, si nce on-going uses are by de finition not new, EPA

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intends to consider working with industry to de velop a voluntary phase-out of such uses within one year, to be followed by a SNUR.

(C) If voluntary phase-out is not agreed upon, or is not completed as agreed upon, EPA intends to consider initiating rulemaking under TSCA section 4 to requ ire exposure monitoring studies on TDI and its related polyis ocyanates in consumer products.

2. Issue a data call-in under TSCA section 8(c) to determin e if there are allegations of significant adverse effects and initiate a TSCA section 8(d) rule for one-time reporting of relevant unpublished health and safety studies.

3. Consider initiating a TSCA section 4 test rule to require exposure monitoring studies in representative loca tions where commercial products w ith uncured TDI would be used.

4. Consider initiating rulemaking under TSCA section 6 to regulate commercial uses of uncured TDI products in locations where the general population could be exposed.

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

Environment . John Wiley & Sons, Ltd, West Sussex, England. ATSDR (2001). Agency for Toxic Disease Registry . Medical Management Guidelines for Toluene Diisocyanate. In Managing Hazardous Materials Incidents, Vol. III Medical Management Guidelines for Acute Chemical Exposures. Atlanta, GA: USDHHS, PHS. ATSDR (2002). Case Studies in Environmental Medicine: Pediatric Environmental Health.
ATSDR Publication N o. ATSDR-HE-CS-2002-0002. ATSDR (2005). Agency for Toxic Disease Registry . Airborne Exposures to Moisture Cure Urethane (MCU) in Multi-Family Residential Buildings. In New York Health Consultation: Exposure Investigation Report U.S. Department of Health and Human Services Public Health Service Agency fo r Toxic Substances and Disease Registry
Division of Health Assessment and Consultation. Bello, D., Herrick, C. A., Smith, T. J., Woskie, S. R., Streicher, R. P., Cullen, M. R., Liu, Y., and Redlich, C. A. (2007). Skin Exposure to Isocyanates: Reasons for Concern. Environ Health Perspect 115.

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Bello, D., Woskie, S. R., Streicher, R. P., Liu, Y ., Stowe, M. H., Eisen, E. A., Ellenbecker, M. J., Sparer, J., Youngs, F., Cullen, M. R., and Re dlich, C. A. (2004). Polyisocyanates in occupational environments: a critical re view of exposure limits and metrics. Am J Ind
Med 46, 480-491. California EPA (2010). Office of Environmenta l Health Hazard Asse ssment (OEHHA). Air Toxics Hot Spots Program – Proposed Revise d Reference Exposure Levels For Toluene Diisocyanate And Methylene Di phenyl Diisocyanate [04/23/10].

< http://www.oehha.ca.gov/air/chronic_rels/RELS042310.html >. Collins, M. A. (2002). Toxicology of Toluene Diisocyanate. Applied Occupational and Environmental Hygiene 1 7 , 846-855. Cummings, B. J., and Booth, K. S. (2002). Industrial hygiene samp ling for airborne TDI in six
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Science , pp. 1633-1652. Taylor & Francis. Gagne, S., Lesage, J., Ostiguy, C., Cloutier, Y., and Van Tra, H. (2005). Quantitative determination of hexamethylen e diisocyanate (HD I), 2,4-toluene diisoc yanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6 -TDI) monomers at ppt levels in air by alkaline adduct coordination ionspray ta ndem mass spectrometry. Journal of Environmental Monitoring

7 , 145-150. Gledhill, A., Wake, A., Hext, P ., Leibold, E., and Shiotsuka, R. (2005). Absorption, distribution,
metabolism and excretion of an inhala tion dose of 14 C 4,4 ' -methylenediphenyl diisocyanate in the male rat. Xenobiotica 35, 273-292. Health and Safety Executive, United Kingdom

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. I ARC (1986). International Agency for Research on Cancer . Monographs on the evaluation of the carcinogenic risk of chemicals to hu mans: some chemicals used in plastics and elastomers. IARC Monograph 39. Lyon, Fr ance: World Health Organization, International Agency for Research on Cancer, pp. 287-323. IARC (1999). International Agency for Research on Cancer . Toluene Diisocyanates May 3, 2010. <http://monographs.iarc.fr/ENG/monographs/vol71/mono71-37.pdf>. IUCLID (2000). CASRN 26471-62-5 m-tolyiden e diisocyanate. European Commission Jan, R. L., Chen, S. H., Chang, H. Y., Yeh, H. J., Shieh, C. C., and Wang, J. Y. (2008). Asthma-like syndrome in school children af ter accidental exposure to xylene and methylene diphenyl diisocyanate. J Microbiol Immunol Infect 41, 337-341. Jarand, C. W., Akapo, S. O., Swenson, L. J., a nd Kelman, B. J. (2002). Diisocyanate emission from a paint product: a preliminary analysis. Appl Occup Environ Hyg 17, 491-494. Javni, I., Hong, D. P., and Petrovic, Z. S. (2008). Soy-based polyuret hanes by nonisocyanates

route Journal of Applied Polymer Science 108, 3867-3875. Kelly, T. J., Myers, J. D., and Holdren, M. W. (1999). Testing of household products and materials for emission of toluene diisocyanate. Indoor Air 9, 117-124. Krone, C., and Klinger, T. (2005). Isocyana tes, polyurethane and childhood asthma. Pediatric Allergy and Immunology 16, 378-379. Krone, C. A. (2004). Diisocyanates a nd Nonoccupational Disease: A Review. Archives of
Environmental Health 59, 306-316. Loeser E (1983). Long-term toxicity and car cinogenicity studies with 2,4/2,6-toluene diisocyanate (80/20) in rats and mice. Toxicol Lett 15 :71-81. MITI (1992). Ministry of International Trade & Industry. Biodegradation and bioaccumulation: data of existing chemicals based on the CSCL. Chemical Industry Ecology-Toxicology & Information Center. , Tokyo, Japan. NIH (2010 ). National Institute of Heath . Household Products Database. June 9, 2010.

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. NIOSH (2004). National Institute for Occ upational Safety and Health . A Summary of Health Hazard Evaluations: Issues Related to Occupational Exposure to Isocyanates 1989-2002. (D. o. H. a. H. Services, E d.), pp. 1-42, Cincinnati, OH. NIOSH (2005). National Institute of Occ upational Safety and Health . NOISH Pocket Guide to Chemical Hazards July 16, 2010. h ttp://www.cdc.gov/NIOSH/npg/npgdcas.html

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Appendix 1

Tier 1: TDI monomers and related isomers and polymers

No CASRN CA Index Name Acronym Common Name

1 91-08-7 Benzene, 1,3-diisocyanato-2-methyl- 2,6-TDI 2,6-Toluene diisocyanate

2 584-84-9 Benzene, 2,4-diisocyanato-1-methyl- 2,4-TDI 2,4-Toluene diisocyanate

3 26471-62-5 Benzene, 1,3-diisocyanatomet hyl- TDI 80/20 Toluene diisocyanate

4 9017-01-0 Benzene, 1,3-diisocyanatomethyl-, homopolymer Polymeric

TDI Poly(toluene diisocyanate)

Tier 2: TDI dimers and trimers

No CASRN CA Index Name Acronym Common Name

5 26747-90-0 1,3-Diazetidine-2,4-dione, 1,3

- bis(3-isocyanatomethylphenyl)- 2,4-TDI
dimer Tolylene diisocyanate
dimer

6 26603-40-7 1,3,5-Triazine-2,4,6(1H,3H,5H)

- trione, 1,3,5-tris(3

- isocyanatomethylphenyl)- TDI
trimer Tolylene diisocyanate
trimer

14U.S. Environmental Protection Agency April 2011

Appendix 2 – Regulatory and Exposure Limits for TDI

EPA . The EPA’s Integrated Risk Informati on System (IRIS) program has developed a
reference concentration (RfC) for TDI of 7 x 10 -5 mg/m 3 using chronic decline in lung function (FEV1) in an occupationally exposed population as the critical effect (EPA, 1995).

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 TDI monomer 0.140 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 also considers TDI to be an o ccupational carcinogen a nd recommends exposure
reduction to the lowest feasib le minimum (NIOSH, 2005).

ACGIH . American Conference of Governmental Industrial Hygienists. Threshold Limit Values (TLVs) for TDI address respiratory sensi tivity 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 TDI to bring atte ntion to the potentia l for absorption of di isocyanates through the
skin.

ACGIH has assigned TDI a TLV of 0.036 mg/m 3 (0.005 ppm) as a TWA for a normal 8

- hour workday and a 40-hour workweek and a 15- minute Short Term Exposure Limit (STEL) of

0.14 mg/m 3 (0.02 ppm) (ACGIH, 2009).

As noted in its 2010 Notices of Intended Changes (NIC) for the 2011 TLVs, ACGIH is also considering reducing the TLV for 2,4 and 2,6 Toluene Diisocyanate (TDI) (CAS 584-84-9; 91-08-7) from 0.005 pp m to 0.001 ppm.

California, OEHHA . In April 2010, California’s O ffice of Environmental Health Hazard Assessment (OEHHA) released “for comment” draft documents describing proposed Reference Exposure Levels (RELs) for TDI 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)

Canada . On May 12, 2010, Canada added TDI to its List of Toxic Substances following
an assessment which determined that TDI is car cinogenic and affects the respiratory system. Environment Canada published a proposed P2 Pollution Prevention Planning Notice for the

15U.S. Environmental Protection Agency April 2011

polyurethane and other foam sector. A propos ed action to investigate non-foam consumer products containing TDIs under the Hazard Products Act is in development.

In 2005, Canada (Ontario Province) updated and lowered its air quality standard for TDI ( http://www.ene.gov.on.ca/envision/env_reg/er/ documents/2005/airstandards/PA02E0010.pdf ).

IARC . The International Agency for Research on Cancer (IARC) has classified TDI as possibly carcinogenic to humans (IARC, 1987b).

16