Attachment VII – Sustainable Futures P2 Assessment for {PPG}023

This chemical is the subject of a P2 Assessment for participation in the Sustainable Futurestm Initiative. 

The P2 assessment of {Poly(oxy-1,4-butanediyl), alpha-hydro-gamma-hydroxy-, polymer with 1,6-

diisocyanatohexane and 1,1’-methylenebis[4-isocyanatocyclohexane]}, referred to as {PPG}023 in the 

assessment, directly follows this cover letter. This summary includes the collection of results, 

assessment methods, and conclusions from the Sustainable Futurestm P2 Framework evaluation of this 

substance. The original modeling outputs and additional detail can be provided upon request.

Incomplete data were available for {PPG}023 and predictive methods were employed in the assessment 

of the chemical. Evaluation of this isocyanate-containing polymeric substance was based on review of 

the polymer properties, as well as evaluation of residual monomer.

{PPG}023 is predicted to have a high overall concern for persistence, with an environmental half-life of 

>180 days. 

{PPG}023 is predicted to have a low concern for bioaccumulation.

{PPG}023 is predicted to have a low hazard concern for aquatic toxicity. 

{PPG}023 is predicted to have low hazard concerns for acute and cancer human health effects. 

However, the substance has been predicted to pose a moderate hazard concern for chronic human 

health hazards, as well as to have the potential for skin and respiratory tract sensitization.

The conclusion of the {PPG}023 aquatic risk assessment is that, based on low hazard, there is a low 

potential for risk.

The conclusion of the {PPG}023 general population human health risk assessments is that, based on the 

predicted hazards and modeled exposure for the substance, there is a low potential for risk.

The conclusion of the {PPG}023 occupational risk assessment is that, based on the hazards identified for 

the substance, there is the potential for occupational dermal risk associated with the manufacture and 

use of the substance. 

It should be noted that this risk assessment does not take PPE and other exposure controls into account

when determining exposure and risk. The {PPG} MSDS, which is included with the PMN, indicates that 

workers should wear gloves and use other personal protective measures when handling {PPG}023 or 

when exposure may occur. Further, both {PPG Industries, Inc.} and the customer which will use 

{PPG}023 have significant experience in the safe handling and use of isocyanate materials and 

participate in health and safety plans to reduce exposure to potentially hazardous substances. 

It is our opinion that based on this assessment of the chemical and information included in the PMN 

submission and manufacturer’s MSDS, including use of gloves and appropriate exposure controls, 

{PPG}023 will not pose an unreasonable risk to human health or the environment.
Sustainable Futures

Summary Assessment

Using

P2 Framework Models

Chemical Assessed: 

{PPG}023

CAS Registry Number: 

N/A

Participant Name: 

{PPG Industries, Inc.}

Date of Assessment:

12/09/2011

This document was developed to help compile estimation results from U.S. EPA OPPT’s P2 

Framework Models and is used by OPPT during Sustainable Futures (SF) training described on 

the US EPS Sustainable Futures homepage at: http://www.epa.gov/oppt/sf/. Participants in the 

voluntary SF Pilot Project are asked to submit the information contained in this assessment along 

with their SF PMNs in their choice of format.

Use of this specific format is not mandatory.
3

Record ID: {PPG}023 Submitter: {PPG Industries, Inc.}

Chemical Structure

Is this a representative structure? Yes

Mn: 4,124 Daltons

% <1,000: 5.1%; % <500: 2.4%

Physical Form: Solid (neat)

CAS RN: N/A

Trade Name: PMN 5079

Use: {Component in Golf Ball 

Resins}

Production Volume:

730,000 kg/yr

SMILES: SMILES not used

Name: {Poly(oxy-1,4-butanediyl), alpha-hydro-gamma-hydroxy-, polymer with 1,6-diisocyanatohexane and 1,1’-

methylenebis[4-isocyanatocyclohexane]}

Synonyms: PMN 5079

SUSTAINABLE FUTURES SUMMARY:

Concern Level HIGH MODERATE LOW

Persistence X

Bioconcentration X

Non-Cancer Health Hazard X

Cancer Health Hazard X

Aquatic Toxicity Hazard X

Is the chemical predicted to be a PBT by PBT Profiler? Not Run in PBT Profiler

Overall Hazard Concern Human Health Hazard: Moderate

Aquatic Hazard: Low

Overall Risk

Human Health Risk: The Potential for Occupational 

Dermal Risk Exists

Aquatic Risk: Low
4

Record ID: {PPG}023 Submitter: { PPG Industries, Inc. }

PHYSICAL/CHEMICAL PROPERTIES:

Melting Point (deg C) >20 °C (professional judgment)

Boiling Point (deg C) Decomposes prior to boiling (professional judgment)

Boiling Point Pressure (mm Hg) 760

Vapor Pressure (mm Hg) <10-8(professional judgment)

Water Solubility <1 mg/L (professional judgment)

Log Kow Not assessed

ENVIRONMENTAL TRANSPORT AND FATE:

Transport

Henry’s Law Constant – HLC (atm-m

3

/mol) <10-8(professional judgment)

Soil Adsorption Coefficient – Log Koc 

Strong sorption to soil; negligible migration potential 

(professional judgment)

Bioconcentration Factor – BCF Low BCF Concern for polymer or unreacted monomer; 10 

used for E-FAST (professional judgment; EPI)

Persistence

Experimental Biodeg Tests >180 day half-life for biodegradation, based on large size 

and hydrophobicity (professional judgment)

Probability of Rapid Biodegradation Will not biodegrade fast (professional judgment)

Ultimate Biodeg Model

Primary Biodeg Model

Ready Biodegradability Not Ready Biodegradable (professional judgment)

Atmospheric Half-life N/A due to lack of partitioning (professional judgment)

Hydrolysis Half-life Isocyanate hydrolysis rapid; amide hydrolysis slow 

(professional judgment)

Volatilization Half-life for Model River >1 year (professional judgment) 

Volatilization Half-life for Model Lake >1 Year (professional judgment)

Removal in Sewage Treatment Plant >90% (PGD 2010)

Byproducts

Degradation Products

Metabolites
5

Record ID: {PPG0}23 Submitter: {PPG Industries, Inc. }

ECOTOXICITY:

ECOSAR Class Amides (monomer only)

Acute Toxicity

Fish LC5O Low, based on NES for polymer or unreacted monomer*

Daphnid LC5O Low, based on NES for polymer or unreacted monomer*

Green Algae EC5O Low, based on NES for polymer or unreacted monomer*

Chronic Toxicity

Fish ChV Low, based on NES for polymer or unreacted monomer*

Daphnid ChV Low, based on NES for polymer or unreacted monomer*

Green Algae ChV Low, based on NES for polymer or unreacted monomer*

Notes * NES – No Effects at Saturation

Overall Aquatic Toxicity Hazard Concern Low

NON-CANCER HEALTH EFFECTS:

Acute Toxicity

Low, based on 4,4 ́-Methylenedicyclohexyl diisocyanate 

(MDDI; CAS RN 5124-30-1), oral LD50 of 1,065 mg/kg in 

rats (OECD 2005)

Irritation Skin irritant, based on Primary Irritation Index of 5.5 of MDDI in 

rabbits; irritating to eyes (IUCLID 2004)

Skin Sensitizer

Positive, based on MDDI, skin and respiratory sensitizer in 

humans and animals, SD50 of 0.20 mg/kg in mice; occupational 

reports of contact dermatitis for isocyanate exposed workers

(Stadler 1985)

Reproductive Effects Moderate, based on MDDI, reproductive NOAEL of 3 mg/kg-day 

in rat, aerosol, slightly reduced fertility (OECD 2005)

Developmental Effects Moderate, based on MDDI, mild defects in offspring not greater 

than historical levels in controls (OECD 2005) 

Immune System Effects

Moderate, based on MDDI, proliferation of lymphocytes in rats 

and immune system changes in exposed populations (IUCLID 

2004)

Neurotoxicity Inadequate information identified

Genotoxicity Negative, based on MDDI, negative in Chinese Hamster Cell 

assay (OECD 2005)

Mutagenicity Negative, based on MDDI, negative Ames test (OECD 2005)

Systemic Effects Low, based on MDDI, subacute study indicated adverse effects 

were the result of local respiratory tract irritation (OECD 2005)

Overall Human Health Non-Cancer Hazard Concern Moderate

CANCER HEALTH EFFECTS:

Experimental data No specific evidence of carcinogenicity, but negative 

mutagenicity data suggest a low concern for MDDI 

OncoLogic Results Low, based on Polymers SAR 

Overall Human Carcinogenicity Hazard Concern Low
6

Record ID: {PPG}023 Submitter: {PPG Industries, Inc. }

INDUSTRIAL OPERATIONS INFORMATION:

Operation Name Manufacture Number of Sites 1

Location {PPG Industries, Inc.,

Oak Creek, WI Facility}

Operating Days Per Year 54 total days/year 

(43, 30 hour batches)

INDUSTRIAL RELEASE SUMMARY:

Media Daily Release 

(kg/site-day)

Release Days 

per Year

No. of Sites 

of Release

Total Annual Releases 

(kg/year -all sites)

Release Site Information

and Control Efficiency

Incineration 34 43 1 1,460 Incineration; 99% Efficiency

OCCUPATIONAL EXPOSURE SUMMARY:

Route Dose Rate Days/yr No. Workers Cancer LADD Chronic ADD Acute APDR

Dermal 1,480 43 1 1.4 mg/kg-day 2.5 mg/kg-day 21 mg/kg-day

Inhalation N/A – Low VP

Total number of Workers – All Sites 2

GENERAL POPULATION EXPOSURE SUMMARY:

Cancer LADDpot Chronic ADDpot Acute ADRpot

Drinking Water

Fish Ingestion

Fugitive Emissions

Incineration Emissions 0 mg/kg-day (VP below 

concern level for exposure)

0 mg/kg-day (VP below 

concern level for exposure)

0 mg/kg-day (VP below 

concern level for exposure)

Landfill Leaching

Dermal – Consumer Use

Inhalation – Consumer Use
7

Record ID: {PPG}023 Submitter: {PPG Industries, Inc.}

INDUSTRIAL OPERATIONS INFORMATION:

Operation Name Manufacture Number of Sites 1

Location {PPG Industries, Inc.,

Oak Creek, WI Facility}

Operating Days Per Year 54 total days/year 

(43, 30 hour batches)

AQUATIC RISK ASSESSMENT

Acute Profile

Endpoint Effect Level 

(ppb)

Assessment

Factor

Acute COC 

(ppb) PEC (ppb) Potential for Risk?

Fish NES 5 N/A 0 Low

Daphnid NES 5 N/A 0 Low

Green Algae NES 4 N/A 0 Low

Chronic 

Profile Endpoint Effect Level (ppb)

Assessment

Factor

Chronic COC 

(ppb)

PEC 

(ppb)

Days of 

Exceedence

Potential 

for Risk?

Fish NES 10 N/A 0 0 Low

Daphnid NES 10 N/A 0 0 Low

Green Algae NES 10 N/A 0 0 Low

HUMAN HEALTH RISK ASSESSMENT

Hazard Concern NOAEL/ LOAEL

(mg/kg-d)

Exposure Dose and 

Source (mg/kg-d)

MOE Potential 

for Risk?

Occupational 

Risk

Reproductive Effects 3 mg/kg-day 

(NOAEL)

2.5 mg/kg-day 

(dermal exposure)

1.2 Yes

General 

Population Risk

Reproductive Effects 3 mg/kg-day 

(NOAEL)

0 mg/kg-day 

(Incinerator Emissions

ADD)

N/A Low

AQUATIC RISK ASSESSMENT SUMMARY

Lowest Acute COC – Aquatic Exposure N/A – Low Hazard

Lowest Chronic COC – Aquatic Exposure N/A – Low Hazard

Predicted Environmental Concentration (PEC) 0 ppb

PEC Exceeds Chronic COC (days / year) 0 days/year

HEALTH RISK ASSESSMENT SUMMARY

MOE – Acute Occupational Exposure N/A – Low Hazard

MOE – Chronic Occupational Exposure 1.2

MOE – Acute General Population Exposure N/A – Low Hazard

MOE – Chronic General Population Exposure N/A – Lack of Exposure
8

Record ID: {PPG}023 Submitter: {PPG Industries, Inc. }

INDUSTRIAL OPERATIONS INFORMATION:

Operation Name Use Number of Sites 1

Location {Acushnet – BP3

New Bedford, MA}

Operating Days Per Year 250

INDUSTRIAL RELEASE SUMMARY:

Media Daily Release 

(kg/site-day)

Release Days 

per Year

No. of Sites 

of Release

Total Annual Releases 

(kg/year -all sites)

Release Site Information 

and Control Efficiency

Water 87.6 250 1 21,900 POTW; 90% Removal 

{NPDES MA0100781 (New 

Bedford, MA POTW)}

OCCUPATIONAL EXPOSURE SUMMARY:

Route Dose Rate Days/yr No. Workers Cancer LADD Chronic ADD Acute APDR

Dermal 1,480 250 2 8.3 mg/kg-day 14 mg/kg-day 21 mg/kg-day

Inhalation N/A – Low VP

Total number of Workers – All Sites 2

GENERAL POPULATION EXPOSURE SUMMARY:

Cancer LADDpot Chronic ADDpot Acute ADRpot

Drinking Water N/A – Not Drinking Water N/A – Not Drinking Water N/A – Not Drinking Water

Fish Ingestion 2.2 x 10-5 mg/kg-day 4.1 x 10-5 mg/kg-day 1.8 x 10-3 mg/kg-day

Fugitive Emissions

Incineration Emissions

Landfill Leaching

Dermal – Consumer Use

Inhalation – Consumer Use
9

Record ID: {PPG}023 Submitter: {PPG Industries, Inc.}

INDUSTRIAL OPERATIONS INFORMATION:

Operation Name Use Number of Sites 1

Location {Acushnet – BP3

New Bedford, MA}

Operating Days Per Year 250

AQUATIC RISK ASSESSMENT

Acute Profile

Endpoint Effect Level 

(ppb)

Assessment

Factor

Acute COC 

(ppb) PEC (ppb) Potential for Risk?

Fish NES 5 N/A 98 Low

Daphnid NES 5 N/A 98 Low

Green Algae NES 4 N/A 98 Low

Chronic 

Profile Endpoint Effect Level (ppb)

Assessment

Factor

Chronic COC 

(ppb)

PEC 

(ppb)

Days of 

Exceedence

Potential 

for Risk?

Fish NES 10 N/A 98 0 Low

Daphnid NES 10 N/A 98 0 Low

Green Algae NES 10 N/A 98 0 Low

HUMAN HEALTH RISK ASSESSMENT

Hazard Concern NOAEL/ LOAEL

(mg/kg-d)

Exposure Dose and 

Source (mg/kg-d)

MOE Potential 

for Risk?

Occupational 

Risk

Reproductive Effects 3 mg/kg-day 

(NOAEL)

14 mg/kg-day 

(dermal exposure ADD)

0.21 Yes

General 

Population Risk

Reproductive Effects 3 mg/kg-day 

(NOAEL)

4.1 x 10-5 mg/kg-day 

(Fish Ingestion ADD)

73,000 Low

AQUATIC RISK ASSESSMENT SUMMARY

Lowest Acute COC – Aquatic Exposure N/A – Low Hazard

Lowest Chronic COC – Aquatic Exposure N/A – Low Hazard

Predicted Environmental Concentration (PEC) 0 ppb

PEC Exceeds Chronic COC (days / year) 0 days/year

HEALTH RISK ASSESSMENT SUMMARY

MOE – Acute Occupational Exposure N/A – Low Hazard

MOE – Chronic Occupational Exposure 0.21

MOE – Acute General Population Exposure N/A – Low Hazard

MOE – Chronic General Population Exposure 73,000
Record ID: {PPG}023 Submitter:{PPG Industries, Inc. }

10

SUMMARY CONCLUSIONS:

Occupational Risk:

Risk of Non-Cancer Acute Effects from Occupational Exposure: Low based on low hazard

Risk of Non-Cancer Chronic Effects from Occupational Exposure: The potential for dermal risk exists based on 

calculated MOEs

Risk of Cancer Effects from Occupational Exposure: Low based on low hazard

General Population Risk:

Risk of Non-Cancer Acute Effects to General Population: Low based on low hazard

Risk of Non-Cancer Chronic Effects to General Population: Low based on calculated MOEs

Risk of Cancer Effects to General Population: Low based on low hazard

Aquatic Risk:

Acute Risk to the Aquatic Environment: Low based on low hazard

Chronic Risk to the Aquatic Environment: Low based on low hazard

Notes on Polymer Size and Assessment Strategy

{PPG}023 is a polymer of Mn of 4,124 amu, with 5.1% of material with MW of <1,000 and 2.4% of material with MW 

of <500. Based on these MW considerations, evaluation of the polymer is based on the overall size and not based on 

oligomeric structures. {However, as much as 17% of residual 4,4 ́-Methylenedicyclohexyl diisocyanate (MDDI; CAS RN 

5124-30-1) monomer and 7.5% residual 1,6-hexane diisocyanate homopolymer (CAS RN 28182-81-2) monomer may 

remain in the mixture. EPA guidance on assessment of isocyanate polymers indicates that if more than 50% of free 

isocyanate moieties exist in the polymeric mixture as the result of unreacted monomer, then human health

assessment should be based on the monomer (EPA 2010). Calculations of isocyanate from polymer versus residual 

monomer for PPG023 indicate that >50% of free isocyanate equivalents are from residual monomer and the 

monomer will be considered in the human health assessment and ecotoxicity assessments of the substance. Based 

on available data and other considerations, the 4,4 ́-Methylenedicyclohexyl diisocyanate (MDDI; CAS RN 5124-30-1) 

monomer was chosen as the basis for calculations and hazard assessment for PPG023. Additional discussion of the 

assessment methodology will be discussed in the individual sections below. The PPG023 calculations of isocyanate 

per species are shown in Appendix 1 below.}

Note on Hydrolysis

{PPG}023 contains isocyanate end-groups. Isocyanates are known to hydrolyze very rapidly in the presence of water, 

generally with a half-life of <1 hour at room temperature. {PPG}023 is expected to be practically insoluble in water, 

which may reduce the hydrolysis rate; however, due to the sensitivity of the isocyanate functionality to hydrolysis, 

this reaction is still expected to be rapid for the polymer. Unreacted monomers and smaller materials are expected 

to hydrolyze very rapidly. Hydrolysis, as it pertains to the human health and ecotoxicity hazard assessments for 

{PPG}023, will be discussed in the assessment sections below.
Record ID: {PPG}023 Submitter:{PPG Industries, Inc. }

11

Physical/Chemical Properties

{PPG}023 is a large polymer with a Mn of 4,124 amu, 5.1% of material with MW of <1,000 and 2.4% of materials with 

MW of <500. The substance is maintained as a solution or dispersion during manufacture and use. The physical 

chemical property assessment of the substance is based on estimation for similar polymeric materials. Based on the 

size, {PPG}023 is expected to be a solid at room temperature when neat. The material is predicted to have a high 

boiling point and would likely decompose prior to boiling. In addition, the vapor pressure is expected to be 

negligible, estimated at <10-8 mm Hg at room temperature. The material is predicted to be nearly insoluble in water, 

with a water solubility of <1 mg/L. {PPG}023 is a large poly functional polymer and is predicted to have negligible 

solubility in water and in octanol, due to this the prediction of an accurate log Kow would be difficult and this 

property has not been estimated for the substance.

Bioconcentration Factor

{PPG}023 is a polymer with Mn of >1,000 and < 10% LMW (low molecular weight) component content; however, up 

to 17% unreacted isocyanate monomer may be present. The polymeric substance is predicted to be too large to be 

readily bioavailable and will have a low concern for bioaccumulation (PGD 2010). The residual isocyanate monomer, 

evaluated as the fully hydrolyzed amide, is predicted by EPI Suite to have a low bioconcentration concern as well. 

Based on these considerations, {PPG}023 is predicted to have a low BCF concern. E-FAST requires a numeric BCF for 

modeling purposes and 10, which is within the range of low concern, was used. 

Environmental Fate

{PPG}023 is a polymer with Mn of 4,124 amu, with a low incidence of LMW materials and significant residual 

monomer. In order to be consistent with a worst case scenario, the environmental fate assessment of {PPG}023 will 

focus on the polymer itself, rather than residual monomer. Based on the size and structure of {PPG}023, > 90% of the 

polymer is predicted to be removed during waste water treatment at a POTW (Boethling et al. 1997). {PPG}023 is 

expected to exist solely as a particulate in the atmosphere (air) and settling of the chemical to surfaces may occur. 

Due to the size of the substance and negligible water solubility, it is expected to bind strongly to soil and sediments 

and have negligible potential to migrate to groundwater. {PPG}023 is not expected to volatilize from water or moist 

soil at an appreciable rate, with an estimated half-life for volatilization from the model lake or river of >1 year. 

{PPG}023, based on the above considerations, is expected to partition mainly to soil and sediment in the 

environment.

{PPG}023 is predicted to partition mainly to soil and sediment in the environment and degradation in these media 

will be most relevant to the overall persistence of the chemical. As noted above, {PPG}023 contains isocyanate endgroups that are expected to hydrolyze in the environment. Due to the rapid predicted rate of the isocyanate 

hydrolysis, the material is expected to exist primarily in the hydrolyzed form in the environment. The polymer also 

contains carbamate functional groups, but these will not hydrolyze to an appreciable extent in the environment. 

Overall, since the isocyanate functionalities are contained on, or are end-groups and hydrolysis of these does not 

significantly alter the large polymer, and given the predicted lack of hydrolysis for the carbamate groups, hydrolysis is 

not considered a significant removal pathway for {PPG}023. The chemical will not partition to the atmosphere to a 

significant extent and atmospheric oxidation is not expected to be a major route of degradation. Due to partitioning 

and stability, the main route of environmental removal of the chemical is expected to be biodegradation. {PPG}023 is 

a polymer with Mn of 4,124; the substance is predicted to bind very strongly to soil and sediment, and partition 

significantly to those media. These factors indicate that the chemical is likely to biodegrade slowly, with an 

estimated half-life for biodegradation of >180 days; this is consistent with a high concern level for persistence.
Record ID: {PPG}023 Submitter:{PPG Industries, Inc. }

12

Overall, {PPG}023 is expected to partition mainly to soil and sediment, where it will have a high concern for 

persistence.
Record ID: {PPG}023 Submitter:{PPG Industries, Inc. }

13

Aquatic Hazard

No measured ecotoxicity data were available for {PPG}023 and the aquatic toxicity hazard is based on professional 

judgment and predictive methods. As discussed above, {PPG}023 is a polymer with Mn of 4,124 and a low incidence 

of LMW material. In addition, there may be up to 17% residual isocyanate monomer in the polymeric mixture. Due 

to these considerations, evaluation of {PPG}023 will be based on the polymer and residual isocyanate monomer. The 

{PPG}023 polymer itself is a large substance that is not expected to be bioavailable or soluble enough to result in 

toxicity hazard to aquatic organisms and is predicted to show no effects at saturation (NES), which is consistent with 

a low hazard concern (Boethling et al. 1997). ECOSAR was used to evaluate the hydrolyzed form of the residual 

{isocyanate monomer (MDDI)}; this results in estimated effect levels of >100 mg/L for acute and >10 mg/L for 

chronic, which is also consistent with a low hazard concern level for ecotoxicity. Based on these considerations, 

{PPG}023 is predicted to have a low overall hazard concern level for aquatic effects.

Overall, based on evaluation of the polymer and residual monomer, {PPG}023 is predicted to have a low aquatic 

toxicity hazard concern level.

Human Health Non-Cancer Hazard

No animal data are available for {PPG}023. However, {PPG}023 is a polymer containing {4,4’-methylenedicyclohexyl 

diisocyanate (MDDI; CAS RN 5124-30-1) with up to 17%} of the residual monomer remaining in the solution. In 

addition, calculations indicate that { >50% of the free isocyanate equivalents are from unreacted MDDI monomer 

}(EPA 2010). Due to these considerations, the {PPG}023 human health assessment will be based primarily on {MDDI,}

as well as studies on the isocyanates class, including occupational exposures to diisocyanates. Isocyanate based 

polymers are common in many occupational settings, and are well-characterized in terms of exposure routes and 

hazards. The primary routes of exposure are inhalation and dermal. Isocyanates can be absorbed through the skin, 

and this is a route of exposure that appears to cause asthma. Isocyanates can also be absorbed via inhalation, as has 

been demonstrated in both animal models and occupational biomarker studies. Comparisons of animal models to 

human biomarker studies have indicated that animal models underestimate human absorption by the route (Monso 

2001), and therefore animal data from this route must be used cautiously, especially since exposures are usually to 

several species of isocyanates. Although many isocyanates have relatively high acute toxicity, {MDDI }has relatively 

low acute toxicity either by oral or dermal exposure, with an LD50 above 1 g/kg for both routes, and an inhalation LC50

of 434 mg/m3/4 hours in rats. Adverse effects after acute inhalation exposure appear to be confined to the 

respiratory tract. Based on {MDDI, PPG}023 is expected to have a low concern for acute toxicity. 

{MDDI} is a skin irritant with a Primary Irritation index of 5.5 in rabbits, and there are reports of contact dermatitis in 

individuals exposed to isocyanates in occupational settings. Based on subacute, repeat-dose inhalation studies, 

[MDDI} is considered a respiratory irritant as well (OECD 2005). Based on this, {PPG}023 is expected to be a skin and 

lung irritant. There have been consistent reports of respiratory sensitization following either inhalation or dermal 

exposure, and an increased prevalence of asthma in occupations involving isocyanate exposure (Bello 2007). The 

general consensus is that {MDDI }specifically, and isocyanates in general, are sensitizers for humans in occupational 

settings. Isocyanates can be absorbed into systemic circulation through dermal exposure, although the rate of 

absorption ranges from 1-2 percent for monomers (Hoffman 2010). Animal models have also indicated that dermal 

exposure to isocyanates can potentiate respiratory response (Stadler 1984); conversely, respiratory exposure can 

potentiate skin sensitivity (Stadler 1985).

A consistent finding of epidemiology studies in workers exposed to isocyanate polymers in settings similar to

{PPG}023 is both increased asthma (prevalence rates of up to 15 percent) (Bello 2007) and cross-sensitization to 

isocyanates as a class. Based on this, {PPG}023 is considered to be to a skin and respiratory sensitizer, and the 

potential to cause respiratory sensitization following skin exposure is possible. 
Record ID: {PPG}023 Submitter:{PPG Industries, Inc. }

14

Human Health Non-Cancer Hazard (continued)

Isocyanates as a class have some potential to cause reproductive and developmental side effects. In rats exposed to 

{MDDI} via aerosol, there was a LOAEL of 6 mg/m3 for both reproductive and developmental side effects. Other 

isocyanates have been shown to have reproductive effects via inhalation, and toluene diisocyanate has a NOAEL for 

postnatal toxicity of 0.02 ppm (Tyl 1999). Based on this, {PPG}023 is expected to have a moderate concern for both 

reproductive and developmental toxicity. 

There have been anecdotal reports of neurological symptoms (headaches, ataxia) following acute exposure to 

{MDDI} or toluene diisocyanate vapors, and while in some cases these effects may have been mediated by alterations 

in respiration, there has been limited evidence that isocyanate exposure can cause persistent symptoms after 

exposure (Reidy 1994) In the absence of an animal study with a neurological battery, it is difficult to draw any 

conclusions, but since hazard cannot be ruled out, {PPG}023 may have a moderate concern as a neurotoxin. 

Smaller isocyanates have shown some potential for mutagenicity, but generally {MDDI} has not been considered a 

mutagen or genotoxic. Although an earlier, non-guideline compliant Ames test of {MDDI} showed moderate 

mutagenicity at a high concentration, repeated Ames test done under compliant conditions have been negative for 

mutagenicity with and without activation at all doses. A Chinese Hamster Cell assay for chromosomal aberrations was 

also negative (OECD 2005). Based on this, {PPG}023 is unlikely to be either a mutagen or genotoxic. 

In a subacute, repeat dose study, rats were dosed with concentrations of 1, 6, and 36 mg/m3 for six hours a day for 

four weeks. {MDDI} was determined to be easily respirable under these conditions, and at 6 mg/m3there were signs 

of irritation in in the nasal tract. This is consistent with observations in the reproductive studies that the major site of 

toxicity is the lungs. Based on this, the NOAEL for respiratory endpoints was 1 mg/m3/6 hours or approximately 2 

mg/kg-day, but no systemic toxicity was observed. This is consistent with the reproductive study and the general 

findings that exposure to isocyanates in occupational settings causes lung irritation and respiratory illness, and is 

potentially sensitizing via either lung or dermal exposure. Therefore, {PPG}023 is expected to have low concern for 

systemic toxicity aside from the high hazard for respiratory toxicity.

Overall, based on potential reproductive concerns for the residual monomer, {PPG}023 is predicted to have a 

moderate human health hazard concern level.

Human Health Cancer Hazard

Based on {MDDI, PPG}023 is unlikely to be a mutagen or genotoxic. No long term animal studies have been 

conducted on {MDDI} or its polymers to determine carcinogenicity; toluene diisocyanate (CAS RN 584-84-9) has been

found to be positive in mutagenic assays, and has shown an increase rates of adenomas when administered by 

gavage, but did not induce cancer in either rats or mice when exposure was by inhalation (NTP 1986, Collins 2002). 

Epidemiology studies in occupational exposures have been inconclusive, with weak evidence for an increase in some 

types of cancer in some studies but no consistent findings. For isocyanates that are not mutagenic or genotoxic, such 

as methyl isocyanate, animal studies have shown very limited evidence of carcinogenesis, with the mechanism likely 

the chronic irritation and inflammation caused by lung exposure. 

Since {PPG}023 is not likely genotoxic or mutagenic, any contribution would likely be via chronic inflammation. 

Therefore,{ PPG}023 is considered to have a low overall cancer risk.
Record ID: {PPG}023 Submitter:{PPG Industries, Inc. }

15

Release and Exposure Sources 

{PPG}023 is a polymer for use in a two component system{in the manufacture of golf balls}. There are two

operations associated with {PPG}023 that are the subject of the PMN and this assessment; Manufacture and Use. 

{PPG}023 will be in a liquid formulation or suspension form during all activities that require handling of the chemical. 

{PPG}023 has been predicted to have >90% removal via POTW, BCF of 10, and negligible potential for groundwater 

migration from landfills based on the size and other properties of the substance. The vapor pressure estimated for 

the substance is below 10-6 mm Hg. Substances with vapor pressures below this level are generally not considered a 

concern for occupation or general population vapor exposure. In some cases, exposure to mists, dusts, or other 

particulates may occur; however, in the case of {PPG}023, no particulate exposure is expected or modeled. 

Occupation dermal exposure from transfer and cleaning operations, as well as general population ingestion exposure 

from disposal of the material, has been predicted and modeled for {PPG}023. 

{PPG}023 is manufactured as an approximately 84% liquid packaged into drums for transport and storage 

(manufacture). The substance is blended with a second component of a resin mixture and used{ in the manufacture 

of golf balls }(use).

The site at which {PPG}023 will be manufactured is controlled by {PPG Industries, Inc.} and {PPG} maintains “zero 

discharge” at these facilities at these sites. All cleaning residuals are recycled into the process, landfilled, or 

incinerated. In the case of {PPG}023, all rinsates from cleaning activities are collected and incinerated. Based on 

these considerations, no releases to surface water or other routes leading to general population exposure from 

manufacture have been estimated for {PPG}023.

The Use operation will occur at a single identified customer site not controlled by {PPG}, identified in the PMN as 

{Acushnet – BP3} located in {New Bedford, MA}. {PPG}023, as received in drums, is pumped directly into the use 

process, where it is mixed with the second component of the resin and used directly; the use process is automated 

and, once removed from the drums used for transport and storage, no exposure is predicted. It should be noted that

once the substance has been mixed with the second component of the resin, an irreversible curing process will begin, 

which will effectively destroy the{PPG}023. Potential worker exposure for unloading and cleaning drums, as well as 

potential release and general population exposure from disposal of residuals in drums, have been estimated and 

modeled for {PPG}023. Release from the disposal of residual has been estimated as occurring to the {New Bedford, 

MA POTW with NPDES permit number MA0100781}. 

The PMN notes that “The customer has an active EH&S program which includes written programs for handling 

isocyanate containing materials, industrial hygiene monitoring and facility hazard evaluation assessments to control 

potential exposures.” This EH&S program is expected to significantly reduce potential occupation exposure and 

release of the substance; however, as the specific details of this program were not known, defaults for exposure and 

release were used for modeling activities associated with the use of {PPG}023.

Predicted releases, occupational, general population, and aquatic environmental exposure from operations modeled 

for {PPG}023 are listed on the pages above.
Record ID: {PPG}023 Submitter:{PPG Industries, Inc. }

16

Environmental (Aquatic) Risk Assessment

Assessment of aquatic risk is based on comparison of the concentration of the chemical in the environment, referred

to as the predicted environmental concentration (PEC), to any acute and/or chronic concentrations of concern (COCs) 

established for the chemical. Acute risk potential is determined by direct comparison of the PEC to an acute COC, 

with the potential for risk being indicated if the PEC is larger than the acute COC. Chronic risk is determined both by 

comparison of the PEC to the chronic COC, similar to the acute risk assessment, and by E-FAST estimation of the 

number of days the PEC will exceed the chronic COC, with risk potential indicated if the PEC exceeds the chronic COC 

for 20 days or more.

Risk is a function of hazard and exposure; if the hazard concern level is low, then the risk will generally also be low. In 

the case of {PPG}023, the chemical is estimated to pose a low ecotoxicity hazard based evaluation of the polymer and 

residual monomer. Based on this, the risk is also predicted to be low.

Overall, based on low hazard, {PPG}023 is expected to pose a low potential for risk to the aquatic environment.

Human Health Risk Assessment

Human health risk potential is established by comparison of the potential health effect levels to the occupational and 

general population dose rates estimated for the chemical. The health effect is divided by the largest dose rate for 

either occupational or general population exposure to give a margin of exposure (MOE). Acute risk is only evaluated 

if the acute LD50 is found to be <50 mg/kg. Chronic risk is evaluated for each effect level identified in the human 

health hazard assessment that has a moderate or greater hazard concern. The magnitude of the MOE determines if 

the potential for risk exists; when based on a LOAEL (lowest observed adverse effect level) a MOE of <1,000 indicates 

the potential for human health risk exists, and when based on a NOAEL (no observed adverse effect level) a MOE of 

<100 indicates the potential for risk exists.

Risk is a function of hazard and exposure; if the hazard concern level is low, then the risk will generally also be low. In

the case of {PPG}023, the chemical is estimated to pose low human health acute and cancer hazard concern levels. 

However, the potential for chronic human health hazard, based on evaluation of {MDDI} is moderate. Predicted 

effect level include a reproductive NOAEL of 3 mg/kg-day; this value was used in the {PPG}023 risk assessment to 

establish potential occupational and general population risk from the modeled potential exposure. It should also be 

noted that {PPG}023 is predicted to be a potential skin and respiratory sensitizer; these hazards are not used to 

quantify risk, but are noted.

In the case of the occupational risk assessment, only dermal exposure was predicted. For both manufacture and use, 

calculated MOEs for the dermal exposure are <100. This indicates that the potential for occupation dermal risk from 

exists for {PPG}023.

In the case of the general population risk assessment, exposure is predicted only for the use operation. Since there is 

no potential general population exposure from manufacture, the potential risk is also low. The calculated MOE for 

the use operation is 73,000; this indicates a low potential for risk from the use operation. Based on these 

considerations, there is a low potential for general population risk from the manufacture and use of {PPG}023.

Overall, based on the MOEs calculated risk assessment of {PPG}023, the potential for occupational dermal risk exists.
Record ID: {PPG}023 Submitter:{PPG Industries, Inc. }

17

References

(Bello 2006) Bello D, Smith TJ, Woskie SR, Streicher RP, Boeniger MF, Redlich CA, Liu Y. An FTIR investigation of 

isocyanate skin absorption using in vitro guinea pig skin. J Environ Monit. 2006 May;8(5):523-9. 

(Bello 2007) Bello D, et al. Skin Exposure to Isocyanates: Reasons for Concern. 

Environ Health Perspect. 2007 March; 115(3): 328–335. Published online 2006 November 28.

(Collins 2002) Toxicology of toluene diisocyanate. Appl Occup Environ Hyg. 2002 Dec;17(12):846-55

(Boethling et al. 1997) Boethling, Robert S. and Nabholz, J. Vincent “Environmental Assessment of Polymers under 

the U.S. Toxic Substances Control Act”, pp. 187-234, in Ecological Assessment of Polymers Strategies for Product 

Stewardship and Regulatory Programs, Hamilton, John D. and Sutcliffe, Roger (eds.), (1997) Van Nostrand Reinhold

(EPA 2010) US EPA Office of Pollution Prevention and Toxics, TSCA New Chemicals Program Chemical Categories, 

revised August 2010, Diisocyanate Category. Available online at: 

http://www.epa.gov/oppt/newchems/pubs/chemcat.htm

(Frick 2003) Malin Frick, Björkner, Hamnerius, Zimerson. Contact dermatitis from dicyclohexylmethane-4,4ʹdiisocyanate. Contact Dermatitis, 48: 305–309. 

(Hoffman 2010) Hoffmann HD, Leibold E, Ehnes C, Fabian E, Landsiedel R, Gamer A, Poole A. Dermal uptake and 

excretion of 14C-toluene diisocyanate (TDI) and 14C-methylene diphenyl diisocyanate (MDI) in male rats. Clinical 

signs and histopathology following dermal exposure of male rats to TDI. Toxicol Lett. 2010 Dec 15; 199(3):364-71

(IUCLID 2004) IUCLID Report for CAS RN 5124-30-1. Accessed at: 

http://echa.europa.eu/reach/software/iuclid5_en.asp

(NTP 1986) Report on Carcinogens, Eleventh Edition; U.S. Department of Health and Human Services, Public Health 

Service, National Toxicology Program.

(OECD 2005) SIDS Initial Assessment Report for 4,4 ́-Methylenedicyclohexyl diisocyanate – Draft Report. Accessed at 

http://www.alipa.org/uploads/Modules/Publications/OECD_DraftSIDS_5124301.pdf 

(PGD 2010) Interpretive Guidance Document for Sustainable Futures Assessment of Polymers, an EPA Sustainable 

Futures/P2 Guidance Document, revised 2010. Available online at: http://www.epa.gov/oppt/sf/. 

Reidy TJ, Bolter JF Neuropsychological toxicology of methylene diphenyl diisocyanate: a report of five cases. Brain 

Inj. 1994 Apr;8 (3):285-94.

(Stadler 1984) Stadler JC, Karol MH. Experimental delayed hypersensitivity following inhalation of 

dicyclohexylmethane-4,4'-diisocyanate: a concentration-response relationship. Toxicol Appl Pharmacol. 1984 Jun 

30;74(2):244-9.

(Stadler 1985) Stadler JC, Karol MH. Use of dose-response data to compare the skin sensitizing abilities of 

dicyclohexylmethane-4,4'-diisocyanate and picryl chloride in two animal species. Toxicol Appl Pharmacol. 1985 

May;78(3):445-50.

(Tyl 1999) Two-generation reproductive toxicity study of inhaled toluene diisocyanate vapor in CD rats. Toxicol Sci.

1999 Dec;52(2):258-68.
Record ID: {PPG}023 Submitter:{PPG Industries, Inc. }

18

Appendix 1: {PPG}023 Estimation of Isocyanates per species

Mn = 4,124 Daltons

17% maximum residual {MDDI} Monomer

{PPG}023 contains a monomer that has two to three potential chain carrying sites per monomer unit (see structure 

above). As the of the polymer Mn increases, the amount of branching will also increase, which will increase the 

number of isocyanate units per polymer species. However, In order to look at the worst case scenario, an average 

number of isocyanate units per polymer molecule of 2.5, which is based on a single potentially branched monomer 

per polymer unit, will be used for these calculations. 

Isocyanates per species:

Assuming 1 gram total weight for mixture containing 830 mg (83% by weight) {PPG}023 and 170 mg (17% by weight) 

{MDDI} Monomer 

Isocyanates from {MDDI} Monomer: 170 mg x 1 mmol/420.49 mg x 2 eq isocyanates/ mmol 

= 0.8 eq isocyanate from MONOMER

Isocyanates from {PPG}023 Polymer: 830 mg x 1 mmol/4,124 mg x 3 eq isocyanates (estimated based on 

monomers)/ mmol

= 0.5 eq isocyanate from POLYMER

> 50% isocyanate comes from MONOMER