Document ID: EPA-HQ-OAR-2003-0118-0230
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-09-23T04:00Z

Significant New Alternatives Policy Program 

Foam-Blowing Sector

Risk Screen on Substitutes for HCFC-22 and HCFC-142b in Rigid
Polyurethane and Polyisocyanurate Laminated Boardstock; Rigid
Polyurethane Appliance, Spray, Commercial Refrigeration, Sandwich
Panels, Slabstock and Other Foams; Polystyrene Extruded Boardstock and
Billet; Integral Skin Polyurethane; Polystyrene Extruded Sheet; and
Polyolefin.

Substitute: Formacel® TI

This risk screen does not contain Clean Air Act (CAA) Confidential
Business Information (CBI) and, therefore, may be disclosed to the
public.

INTRODUCTION

Ozone-depleting substances (ODS) are being phased out of production in
response to a series of diplomatic and legislative efforts that have
taken place over the past decade, including the Montreal Protocol and
the Clean Air Act Amendments of 1990 (CAAA).  The U.S. Environmental
Protection Agency (EPA), as authorized by Section 612 of the CAAA, is
developing a program to evaluate the human health and environmental
risks posed by alternatives to ODS.  The main purpose of EPA's program,
called the Significant New Alternatives Policy (SNAP) Program, is to
identify acceptable and unacceptable substitutes for ODS in specific end
uses.  

EPA’s decision on the acceptability of a substitute is based largely
on the findings of a screening assessment of potential human health and
environmental risks posed by the substitute in specific applications. 
EPA has already screened a large number of substitutes in many end uses
within all of the major ODS-using sectors, including refrigeration and
air conditioning, solvent cleaning, foam-blowing, aerosols, fire
suppression, adhesives, coatings and inks, and sterilization. The
results of these risk screens are presented in a series of Background
Documents that are available in EPA's docket.

The purpose of this report is to supplement EPA’s Background Document
on the foam-blowing sector (EPA 1994) (hereinafter referred to as the
Background Document).  This risk screen evaluates the potential use of
Formacel® TI as a substitute for HCFC-22 and HCFC-142b in all
foam-blowing end-uses.    REF _Ref173102842 \h  \* MERGEFORMAT  Table 1 
presents information on the proposed substitute.

Table   SEQ Table \* ARABIC  1 . Chemical Information for Proposed
Substitute.

Proposed Substitute	Chemical Name	CAS Number	Chemical Formula	Weight
Percent

HFC-134a	1,1,1,2-tetrafluoroethane	811-97-2	C2H2F4	0% - 70%

HFC-134	1,1,2,2-tetrafluoroethane	359-35-3	C2H2F4	0% - 30%

Section 2 of this report summarizes the results of the risk screen for
the proposed substitute.  The remainder of the report is organized into
the following sections:

Section 3: Atmospheric Assessment 

Section 4: Toxicity Assessment

Section 5: General Population Assessment

Section 6: Volatile Organic Compound Assessment 

Section 7: References

A flammability assessment was not conducted because the substitute is
non-flammable (DuPont 2009a).

SUMMARY OF RESULTS

Formacel® TI is recommended for SNAP approval as a foam-blowing agent;
however other substitutes with a lower GWP should be used when feasible.
Use of Formacel® TI in the sector is not expected to pose a threat to
the health of workers and consumers who may be exposed to the
substitute.  The substitute is non-flammable.

ATMOSPHERIC ASSESSMENT

This section presents an assessment of the potential risks to
atmospheric integrity posed by the use of Formacel® TI as a
foam-blowing agent.  The ODP, GWP, and ALT of the components of the
proposed substitute are presented in   REF _Ref232306456 \h  \*
MERGEFORMAT  Table 2 . The substitute’s components have no ozone
depleting potential and somewhat decreased global warming potentials
compared to HCFC-22 and HCFC-142b.  As the GWPs of the components of
Formacel® TI are still relatively high, other substitutes with a lower
GWP should be used when feasible. 

Table   SEQ Table \* ARABIC  2 . Atmospheric Impacts of Formacel® TI
Compared to HCFC-22 and HCFC-142b.

Foam-Blowing Agent	Ozone Depleting Potential (ODP)	Global Warming
Potential - SARa

(100-year GWP)	Global Warming Potential – AR4b

(100-year GWP)	Atmospheric Lifetime years (ALT)

HFC-134a	0c 	1,300a	1,430b	14b

HFC-134d	0c	-	- 	9.6e

HCFC-22	0.05e	1,500a	1,810b	12b

HCFC-142b	0.07e	1,800a	2,310b	17.9b

a IPCC 2nd Assessment Report, as cited in IPCC 4th Assessment Report
(Forster et al. 2007).

b IPCC 4th Assessment Report (Forster et al. 2007).

cFormacel® TI SNAP Submission (DuPont 2009a).

d The GWP of HFC-134 is not available in the SAR or AR4, however is
reported as  1,100 in the IPCC 3rd Assessment Report (Ehhalt and Prather
2001) and WMO (2007).

eWMO (2007).

TOXICITY ASSESSMENT

This section presents an assessment of potential health risks to workers
and consumers exposed to Formacel® TI when used as a foam-blowing
agent.

Toxicity of the Substitute

ICF recommends that long-term exposures to HFC-134a not exceed the AIHA
WEEL of 1,000 ppm as an 8-hour time weighted average (AIHA 2007). 
Exposure limits have not been developed for HFC-134; however HFC-134 and
HFC-134a are very similar in structure and are therefore expected to
have similar toxicity.  Blowing agent degradation is not expected, based
on test results provided by the submitter.

Occupational Exposure and Hazard Analysis

ICF modeled potential occupational exposures to the substitute using
data provided by the submitter (DuPont 2009b).  Table 3 below presents
the modeled exposures.  As seen in the table, exposures are not expected
to exceed 3 ppm when used under the conditions provided by the
submitter.

Table 3.  Modeled Exposures to the Substitute in Each Proposed End-Use

End-use 	Concentration (ppm)

Rigid Polyurethane: Appliance 	0.2

Rigid Polyurethane: Spray 	1.0

Rigid Polyurethane: Commercial Refrigeration, and Sandwich Panels 	0.5

Integral Skin Polyurethane 	0.04

Polystyrene Extruded Sheet 	0.4

Polyolefin 	0.2

Rigid Polyurethane: Slabstock and Other 	1.1

Polystyrene: Extruded Boardstock and Billet 	2.6

Rigid Polyurethane and Polyisocyanurate Laminated Boardstock 	2.6

As the main component of this substitute is already in use as a
foam-blowing agent and exposures to the substitute are expected to be
significantly less than the HFC-134a exposure limit of 1,000 ppm (and
HFC-134 is expected to have similar toxicity), ICF believes that
toxicity risks stemming from use of Formacel® TI as a foam-blowing
agent will be minimal.  As all facilities using the foam-blowing agent
may not operate under the same conditions as those in the examples
provided by the submitter, to further mitigate risks,  ICF recommends
that all facilities using Formacel® TI as a foam-blowing agent ensure
levels of Formacel® TI do not exceed the exposure limit through
adequate ventilation, engineering controls and good work practices.

Consumer Exposure

Consumer applications are not currently proposed for the substitute;
however there is the potential for chronic consumer exposures to
foam-blowing agents during the lifetime of the foam in which they are
used because these agents can slowly leak from the foam over time. 
Therefore, should foams made with Formacel® TI be used in locations
where consumers are regularly present for extended periods, such as a
home or apartment, the consumers could be exposed to very low levels of
Formacel® TI over time.  However, ICF believes that such exposures do
not pose a significant toxicity risk as HFC-134a is already used as a
foam-blowing agent and the additional component in Formacel® TI,
HFC-134, is expected to have similar toxicity to HFC-134a.

Additionally, as the substitute is proposed for use in spray foam, there
is the potential for consumer exposures during foaming operations as
these operations are done on-site.  Therefore, workers using Formacel®
TI in this end-use (and at any other time when consumers may be exposed
to the agent) should ensure that blowing agent losses are minimized and
that adequate ventilation is in place to prevent exposures to consumers.
 ICF recommends that workers, prior to commencing foam-blowing
activities, warn any building occupants that foam-blowing is about to
occur and suggest the occupants leave the premises until the
foam-blowing is complete.  

GENERAL POPULATION EXPOSURE ASSESSMENT

Chronic exposures to the substitute are not expected for the general
population. 

VOLATILE ORGANIC COMPOUND ASSESSMENT

The components of Formacel® TI have been exempted as VOCs under the CAA
(40 CFR 51.100(s)(1)).

REFERENCES

AIHA.  2007.  Current AIHA WEEL Guides (2007).  Available at: <
http://www.aiha.org/1documents/Committees/WEEL-WEELslevels2007.pdf>.

Ehhalt, D.H. and M. Prather.  2001.  Atmospheric Chemistry and
Greenhouse Gases.  In: Climate Change 2001: The Scientific Basis,
Cambridge University Press, pp. 239-287.

EPA. 1994.  Significant New Alternatives Policy Technical Background
Document:  Risk Screen on the Use of Substitutes for Class I
Ozone-depleting Substances: Foam-Blowing Agents.  Stratospheric
Protection Division.  March, 1994.

DuPont. 2009a. Significant New Alternatives Policy Program Submission to
the United States Environmental Protection Agency. March 2009. 

DuPont.  2009b.  Formacel TI SNAP Submission Addendum Letter.  July
2009.

Forster, P., V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D.W. Fahey,
J. Haywood, J. Lean, D.C. Lowe, G. Myhre, J. Nganga, R. Prinn, G. Raga,
M. Schulz and R. Van Dorland. 2007.  Changes in Atmospheric Constituents
and in Radiative Forcing. In: Climate Change 2007:The Physical Science
Basis. Contribution of Working Group I to the Fourth Assessment Report
of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin,
M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller
(eds.)]. Cambridge University Press, Cambridge, United Kingdom and New
York, NY, USA.

WMO (World Meteorological Organization).  2007.  Scientific Assessment
of Ozone Depletion: 2006. Global Ozone Research and Monitoring
Project—Report No. 50, 572 pp., Geneva, Switzerland, 2007.

 For each end-use, the submitter provided the following data:  average
size of facility where foam manufacture/utilization is taking place;
average air flow ventilation rate in building; average annual facility
blowing agent usage; average facility operation; and average blowing
agent release at manufacture.

Formacel TI Risk Screen

September 21, 2009

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