Document ID: EPA-HQ-OAR-2003-0118-0235
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-09-24T04:00Z

Significant New Alternatives Policy Program 

Foam-Blowing Sector

Risk Screen on Substitutes for HCFC-141b in Rigid Polyurethane and
Polyisocyanurate Laminated Boardstock; Rigid Polyurethane Appliance,
Spray, Commercial Refrigeration, Sandwich Panels, Slabstock and Other
Foams; Polystyrene Extruded Boardstock and Billet; Phenolic Insulation
Board and Bunstock; Flexible and Integral Skin Polyurethane; Polystyrene
Extruded Sheet; and Polyolefin.

Substitute: HFC-365mfc

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
HFC-365mfc as a substitute for HCFC-141b 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

HFC-365mfc	1,1,1,3,3-pentafluorobutane	406-58-6	C4H5F5

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: Flammability Assessment

Section 5: Toxicity Assessment

Section 6: General Population Assessment

Section 7: Volatile Organic Compound Assessment 

Section 8: References

SUMMARY OF RESULTS

HFC-365mfc is recommended for SNAP approval as a foam-blowing agent;
however as the substitute has a relatively high GWP, other substitutes
with a lower GWP should be used when feasible. Use of HFC-365mfc in the
sector is not expected to pose a threat to the health of workers and
consumers who may be exposed to the substitute.  While the substitute is
flammable, under proper use (i.e., with adequate ventilation,
engineering controls and good work practices in place), the risk of fire
and explosion is expected to be minimal.

ATMOSPHERIC ASSESSMENT

This section presents an assessment of the potential risks to
atmospheric integrity posed by the use of HFC-365mfc as a foam-blowing
agent.  The ODP, GWP, and ALT of the proposed substitute are presented
in   REF _Ref232306456 \h  \* MERGEFORMAT  Table 2 . The substitute is
less harmful to the ozone layer, however it does have a higher GWP and a
longer atmospheric lifetime than HCFC-141b.  Therefore, when feasible, a
substitute with a lower GWP should be used.

Table   SEQ Table \* ARABIC  2 . Atmospheric Impacts of HFC-365mfc
Compared to HCFC-141b.

Foam-Blowing Agent	Ozone Depleting Potential (ODP)	Global Warming
Potential (GWP)	Atmospheric Lifetime years (ALT)

HFC-365mfc	0a	790a	10.2a

HCFC-141b	0.11b	725b	9.3b

a HFC-365mfc SNAP Submission (Solvay Fluorides, LLC 2008).

b Available at: http://www.epa.gov/ozone/ods.html.

FLAMMABILITY ASSESSMENT

HFC-365mfc is flammable when its concentration in air is in the range of
3.8%-13.3% by volume (this is equal to 38,000 ppm to 133,000 ppm).  In
the presence of an ignition source (e.g., static electricity, a spark
resulting from a closing door, or a cigarette), an explosion or a fire
could occur when the concentration of HFC-365mfc is within these
flammability limits.  The submitter has indicated that the substitute
“may be used at 100% concentration if the facility is designed around
flammable blowing agents; alternatively end users may and will co-blend
with other non-flammable fluorocarbons such as HFC 134a and HFC 245fa;
additions as little as 5% w/w render the mixture non-flammable.”
(Solvay Fluorides, LLC 2008)  

When used at 100% concentration, it is important that only properly
trained workers handle HFC-365mfc.  It is also important that the
strictest standards be followed during the use of this agent.  It is
recommended that the agent be properly stored and that caution be used
at facilities and work sites where the agent is in use to minimize
explosion risk. Proper ventilation should be maintained at all times
during the use of HFC-365mfc in all foam-blowing end-uses.  Under proper
use, i.e., with adequate ventilation, engineering controls and good work
practices in place, flammability risks due to use of HFC-365mfc are
expected to be minimal.

TOXICITY ASSESSMENT

This section presents an assessment of potential health risks to workers
and consumers exposed to HFC-365mfc when used as a foam-blowing agent.

Toxicity of the Substitute

Review of the toxicological information available for this substitute
indicates that it has low toxicity; ICF recommends that long-term
exposures to the substitute not exceed 1,000 ppm as an 8-hour time
weighted average. While a higher 8-hour time weighted average (TWA)
acceptable exposure limit (AEL) may be appropriate based on the toxicity
data, 1,000 ppm was chosen as the recommended AEL to be consistent with
upper limits to 8-hour TWAs recommended by OSHA, NIOSH, and ACGIH. ICF
found that none of these organizations recommend AELs above 1,000 ppm
even for the most nontoxic substances (ICF Consulting 2000).

Current information regarding the decomposition of the foam-blowing
agent indicates that several breakdown products can form, however these
decomposition products are expected to form only in the presence of fire
or at relatively high temperatures (70 degrees Celsius).  To prevent
against the formation of these byproducts, the substitute should be
stored and used only at temperatures below 70 degrees Celsius and
caution should be taken during use of the agent to ensure that
concentrations of the substitute do not exceed the lower flammability
limit to prevent fires.  ICF recommends that all users of HFC-365mfc
carefully read and follow safety information provided by the
substitute’s manufacturer to prevent formation of decomposition
products.

Occupational Exposure and Hazard Analysis

Limited data are available regarding employee exposures to blowing
agents for all of the foam types in which HFC-365mfc is proposed for
use.  However, based on the toxicity data for this substitute, relative
to others already in use, and the continued use of standard industry
practices to mitigate exposure to the substitute, it is believed that
HFC-365mfc will not pose a toxicity threat to workers if it is kept to
the AEL.

Toxicity data for the substitute indicate that HFC-365mfc exposures
below 1,000 ppm will not produce adverse health effects.  Given that
other substitutes already in use are more toxic than HFC-365mfc, ICF
believes that standard industry practices which are already protective
against these more toxic substances will mitigate toxicity risks due to
use of HFC-365mfc as a foam-blowing agent.  For example, the main
component of the blowing-agent Ecomate has an OSHA permissible exposure
limit (PEL) of 100 ppm.

Further, EPA concluded in the Background Document that while data were
not available on all foam types, “in most cases, employee exposures to
blowing agents can generally be maintained below the occupational
exposure limits of all of the potential substitutes, so long as adequate
ventilation and good work practices are employed”  (EPA 1994). 
Therefore, ICF recommends that all facilities using HFC-365mfc as a
foam-blowing agent ensure levels of HFC-365mfc do not exceed 1,000 ppm
through adequate ventilation, engineering controls and good work
practices.  Under proper use, exposures to HFC-365mfc and subsequent
toxicity risks are expected to be minimal.

Consumer Exposure

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 HFC-365mfc 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 HFC-365mfc over time. 
However, ICF believes that such exposures do not pose a significant
toxicity risk as the exposures would be very small compared to AEL
values developed for occupational exposures.

Additionally, information received from the submitter indicates that
there is the potential for consumer exposures during rigid polyurethane
spray foaming operations (Scientific & Regulatory Solutions 2009). 
Workers using HFC-365mfc 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

HFC-365mfc has been exempted as a VOC under the CAA (40 CFR
51.100(s)(1)). 

REFERENCES

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.

ICF Consulting.  2000.  Revised AEL Recommendation for HFA 365mfc. 
October 19, 2000.

Scientific & Regulatory Solutions.  2009.  Re: Supplemental Information
– Solkane® 365mfc SNAP Submission.  Submitted on behalf of Solvay
Fluorides, LLC.  June 2009. 

Solvay Fluorides, LLC. 2008. Significant New Alternatives Policy Program
Submission to the United States Environmental Protection Agency, October
2008. 

 A PEL is an 8-hour time-weighted average exposure limit. 

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