United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/600/R-98/068
June 1998
Environmental  Profile for
Propylene Carbonate

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                                                      EPA/600/R-98/068
                                                             June 1998
ENVIRONMENTAL PROFILE FOR PROPYLENE
CARBONATE
                                By

                       Research Triangle Institute
                 Research Triangle Park, NC 27709-2194

                                and

                Science Applications International Corporation
                          Reston, VA 20190
                        Contract No. 68-C6-0027
                            Project Officer:

                           Kenneth R. Stone
                      Sustainable Technology Division
                National Risk Management Research Laboratory
                          Cincinnati, OH 45268
        NATIONAL RISK MANAGEMENT RESEARCH LABORATORY
               OFFICE OF RESEARCH AND DEVELOPMENT
              U S ENVIRONMENTAL PROTECTION AGENCY
                         CINCINNATI, OH 45268
                                                         Printed on Recycled Paper

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                                          Notice

      The information contained in this document has been funded wholly or in part by the U S
  Environmental Protection Agency under Contract 68-C6-0027 to Science Applications    '  '
  Mernational Corporation and through a subcontract from Science Applications International
  Corporation to Research Triangle Institute.  Mention of trade names or commercial products does
  not constitute endorsement or recommendation for use.
11

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                                       Foreword
    The U. S. Environmental Protection Agency is charged by Congress with protecting the
Nation's land, air, and water resources.  Under a mandate of national environmental laws, the
Agency strives to formulate and implement actions leading to a compatible balance between
human activities and the ability of natural systems to support and nurture life.  To meet this
mandate, EPA's research program is providing data and technical support for solving
environmental problems today and building a science knowledge base necessary to manage our
ecological resources wisely, understand how pollutants affect our health, and prevent or reduce
environmental risks in the future.

    The National Risk Management Research Laboratory is the Agency's center for investigation
of technological and management approaches for reducing risks from threats to human health and
the environment. The focus of the Laboratory's research program is on methods for the
prevention and control of pollution to the air, land, water and subsurface resources; protection of
water quality in public water systems; remediation of contaminated sites and groundwater; and
prevention and control of indoor air pollution.  The goal of this research effort is to catalyze
development  and implementation  of innovative, cost-effective environmental technologies;
develop scientific and engineering information needed by EPA to support regulatory and policy
decisions; and provide technical support and information transfer to ensure effective
implementation of environmental regulations and strategies.

    This publication is a product of the Laboratory's Life Cycle Engineering and Design research
program, an effort to develop life cycle assessment and evaluation tools that can be applied for
improved decision-making by individuals in both the public and private sectors. Life  Cycle
Assessment is a part of the Laboratory's strategic long-term research plan.  This document is
published and made available by EPA's Office of Research and Development to assist the user
community and to link researchers with their clients.
                            E. Timothy Oppelt, Director
                            National Risk Management Research Laboratory
                                                                                      111

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                                      Abstract

    This project is sponsored by the U.S. Department of Defense's (DoD's) Strategic
Environmental Research and Development Program (SERDP) and led by the U.S. Environmental
Protection Agency's (EPA's) Life Cycle Assessment (LCA) Research Team at the National Risk
Management Research Laboratory (NRMRL).  The research effort described in this report was
conducted to support the Life Cycle Engineering and Design (LCED) Program, a cooperative
program of both DoD and EPA. Among the objectives of the LCED is demonstrating the
effectiveness of analytical tools and environmental techniques to reduce impacts to the
environment and costs of operation while maintaining performance standards.  The lessons
learned from LCED projects will be incorporated into  a design guide for DoD process engineers
and designers. Environmental information on propylene carbonate (PC) is required for the
development of the design guide. This report presents information related to the potential
environmental implications of PC.
IV

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                                  Table of Contents
Section
Page
1.0 Introduction	  1-1
    1.1 Goals and Scope of this Research 	  1-2
    1.2 Research Approach	  1-3
    1.3 Report Organization	  1-3

2.0 Production and Use of PC  	2-1
    2.1 Production  	2-2
    2.2 Use	2-2

3.0 Impact Categories	3-1
    3.1 Ecological Impacts  	.3-1
    3.2 Human Health Impacts	3-1

4.0 Data Review	4-1
    4.1 Sources	  4-1
        4.1.1    Literature Search	4-1
        4.1.2    Internet Search 	4-3
    4.2 Physical and Chemical Properties	4-3
    4.3 Environmental Fate and Transport	  4-8
    4.4 Toxicity	;	4-8
        4.4.1    Human Data	4-9
        4.4.2    Laboratory Animal Data	4-9
        4.4.3    Toxicokinetics	4-11

5.0 Impact Assessment	5-1
    5.1 Human Populations at Risk	5-1
    5.2 Natural Resources/Ecosystems  	5-1

6.0 Environmental Regulations	6-1

7.0 Summary  	7-1

8.0 References	8-1

Appendix A: Propylene Carbonate Case Studies	A-l

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                                   List of Tables
3-1 Ecological Impact Categories Related to Chemical and Nonchemical Stressors
    and Resource Depletion 	3-2
3-2 Human Health Impact Categories Related to Chemical and Nonchemical
    Stressors	
3-2
4-1 Literature Search for NMP and PC	4-1
4-2 Specific Topic Literature Search for NMP and PC  	4-2
4-3 Internet Searches for PC Environmental Profile Data 	4-4
4-4 PC Physical and Chemical Properties  	4-6
6-1 Regulatory Information for PC	6-1
VI

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                                    Acronyms

BOD       Biochemical oxygen demand
CAA       Clean Air Act
CARC      Chemical agent-resistant coating
CAS        Chemical Abstracts Service
CERCLA    Comprehensive Environmental Response, Compensation, and Liability Act
COD       Chemical oxygen demand
DoD        U.S. Department of Defense
EPCRA     Emergency Planning and Community Right-to-Know Act
GI          Gastrointestinal tract
LCA        Life cycle assessment
LCED      Life Cycle Engineering and Design Program
MEK       Methyl ethyl ketone
MSDS      Material safety data sheet
NMP       N-methylpyrrolidone
NFPA      National Fire Protection Association
PC          Propylene carbonate
ppm        Parts per million
RCRA      Resource Conservation  and Recovery Act
SARA      Superfimd Amendments and Reauthorization Act
SERDP     Strategic Environmental Research and Development Program
TLV        Threshold limit value
EPA        U.S. Environmental Protection Agency
TOC        Total organic carbon
VOC        Volatile organic compound
°C          Degrees Celsius
°F          Degrees Fahrenheit
                                                                               vn

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                                 1.0 Introduction

      The research effort described in this report was conducted under cooperating programs of
both the Department of Defense (DoD) and the Environmental Protection Agency (EPA).
Among the shared objectives of the cooperators is demonstrating the effectiveness of analytical
tools and environmental techniques to reduce environmental impacts and costs of operation while
maintaining performance standards. This project was sponsored by DoD's Strategic
Environmental Research and Development Program (SERDP) and conducted by EPA's Life
Cycle Assessment Research Team at the National Risk Management Research Laboratory
(NRMRL).

STRATEGIC ENVIRONMENTAL RESEARCH AND DEVELOPMENT PROGRAM
     ©SERDP
            Strategic Environmental Research
               and Development Program
     Improving Mission Readiness Through
          Environmental Research
addition, it is expected that many techniques
public and private sectors.
   SERDP was established 2 years ago in order to
 sponsor cooperative research, development, and
 demonstration activities for environmental risk
 reduction. Funded with DoD resources, SERDP is
 an interagency initiative between DoD, the
 Department of Energy (DOE), and EPA.  SERDP
 seeks to develop environmental solutions that
 improve mission readiness for federal activities. In
that are developed will have applications across the
LIFE CYCLE ASSESSMENT RESEARCH PROGRAM

Since 1990, the NRMRL has been at the forefront in the development of life cycle assessment
(LCA) as a methodology for environmental assessment. In 1994, NRMRL established an LCA
Team to organize individual efforts into a comprehensive research program. The LCA Team
coordinates work in both the public and private sectors with cooperators ranging from members
of industry and academia to federal facility operators and commands. The team has published
project reports and guidance manuals, including Life Cycle Assessment: Inventory Guidelines
and Principles and Life Cycle Design Guidance Manual. The work described in this report is a
part of an expanding program of research in LCA taking place under the direction of NRMRL in
Cincinnati, OH.
                                                                             1-1

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       The research effort described in this report was conducted under the Life Cycle
 Engineering and Design (LCED) program, a cooperative program of both the DoD and EPA.
 Among the objectives of the LCED program is demonstrating the effectiveness of analytical tools
 and environmental techniques to reduce impacts to the environment and costs of operation while
 maintaining performance standards.  To do this, LCED has sponsored three LCA and life cycle-
 based projects at DoD installations:

       •   Propylene Carbonate (PC) Blend 2, a depainting alternative to methyl ethyl ketone (MEK)
       •   Chemical agent-resistant coating (CARC)
       •   GBU-24 energetics model.

       This project is sponsored by DoD's SERDP and by EPA's LCA Research Team at the
 NRMRL.

 1.1    Goals and Scope of this Research

       The overall goal of this research is to document the environmental impacts of PC to assist
 DoD in assessing the life cycle environmental implications of PC and PC-based formulations as
 viable alternative materials, products, and techniques to paint, depaint, and corrosion control
 DoD aircraft, vehicles, and equipment in common applications at federal facilities.

       A life cycle study encompasses the cradle-to-grave stages of a product, process, or
 activity, from the  acquisition of raw materials to the final disposition. Consistent with life cycle
 concepts, the study boundaries for the use of PC in painting and depainting operations include
 the following elements:

       •    Raw materials acquisition
       •    Production of intermediate chemicals and materials
       •    Production of PC
       •    Use of PC
       •    Storage and disposal of residual PC.

 1.2    Research  Approach

       Identifying the life cycle environmental implications of PC in DoD painting and
 depainting operations requires not only a comprehensive search for the use of PC in those
 operations but also a search for information related to the production, use (in other applications),
 and disposal of PC.

       To develop an environmental profile for PC, the following tasks were conducted and
documented:
                                                                                    1-2

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       •  Conducted a literature search of PC for all environmental impact information and data
          that can be reasonably acquired

       •  Collected analyses of the environmental impacts of PC as used in painting and
          depainting operations

       •  Contacted responsible individuals in the aerospace industry who .have evaluated PC
          and PC substitutes, as well as those currently using PC

       •  Provided detailed information on the known ecological and human health impacts of
          PC, including occupational health and safety implications of the use of PC in
          aerospace cleaning and depainting operations

       •  Collected relevant case histories on the use of PC for cleaning and depainting
          operations.

1.3    Report Organization

       This report is organized according to the following sections:

       2.0    Production and Use of PC
       3.0    Impact Categories
       4.0    Data Review
       5.0    Impact Assessment
       6.0    Environmental Regulations
       7.0    Summary
       8.0    References.

       Section 2.0 provides background information on PC and presents several case studies
focusing on its use in depainting operations. Key human health and environmental impact
categories are identified in Section 3.0.  Section 4.0 discusses sources of information, physical
and chemical properties, environmental  fate and transport, and the toxicology of PC. Section 5.0
identifies the populations at risk of exposure and summarizes the available data on potential
impacts to natural resources and ecosystems. Current environmental regulations are reviewed in
Section 6.0, and a summary is provided  in Section 7.0.
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                           2.0 Production and Use of PC

       Propylene carbonate is an organic solvent produced by reacting propylene oxide with
carbon dioxide in the presence of a homogeneous catalyst. The process used to manufacture PC
is summarized in Section 2.0 of this report. The relatively low vapor pressure, stability, and high
flash point of PC, along with its solvency characteristics compared to other solvents, make it
suitable for use as a solvent for paints and varnishes, plastics, and epoxides. PC also is used in
the following applications:

       •  Production of fibers and textiles ~ as solvent and softener, specifically in extrusion
          and polymerization into fibers of acrylonitrile and polyamide

       •  Synthetic and natural fabrics finishing (e.g., improving lightfastness, dirt-proofness,
          and mechanical and wrinkle resistance)

       •  Dyeing -- improving the dyeability of fibers

       •  Removal of carbonyl sulfide (COS) and hydrogen sulfide (H2S) and small amounts of
          water from natural and synthesized CO2-rich gas (e.g., ammonia synthesized gas)

       •  Extraction of aromatic hydrocarbons from petroleum fractions and from mixtures
          with aliphatic hydrocarbons

       •  Extraction of metals from acid solutions  (e.g., Bi, Cd, Co, Cu, Au, Fe, Pb, Hg, Mo,
          Pd,Rh,V,W,andZn)

       •  Gel promoter in bentonite-based lubricants

       •  Organic solvent in electrolytes for high-energy density batteries and electrolytic
          capacitors

       •  Personal care agents and cosmetics

       •  Removal of phenols and alcohols from aqueous solutions

       •  Component of cooling agents and brake fluids.

       A life cycle evaluation of PC requires an assessment of all potential impacts associated
                                                                                      2-1

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 with its production and use. Section 2.1 summarizes the steps involved in the manufacture of
 PC, starting with the extraction and processing of natural gas to the manufacture of the final PC
 product. Section 2.2 contains summaries of case histories regarding the use of PC in paint and
 depainting operations, as well as other applications that provide similar exposure scenarios.

 2.1    Production

       A description of the process required to manufacture PC is presented in Thomas and
 Frankin (1996). Propylenes and other olefins are produced through the thermal cracking of
 saturated hydrocarbons such as ethane, propane, naphtha, and other gas oils. Production begins
 when hydrocarbons and steam are fed into a cracking furnace. After being heated to
 temperatures around 1,000 °C, the cracked products are quenched in heat exchangers.  Fuel oil is
 separated from the main gas stream in a multistage centrifugal compressor.  The main gas stream
 then undergoes H2S removal and drying. Propylene is combined with a tert-butyl hydroperoxide
 and alcohol mixture at a rate of 2 to 6 moles of propylene per mole of hydroperoxide. This
 mixture is reacted to nearly 100 percent conversion of the hydroperoxide over a catalyst usually
 made of molybdenum. Propylene and propylene oxide are separated from the product in
 distillation columns.

       Propylene carbonate is produced by the reaction of propylene oxide  with carbon dioxide
 over a tetraethyl/ammonium bromide catalyst. The total energy required to produce 1,000 Ib of
 PC from raw material acquisition through production equals 14,639,000 Btu for material
 resource energy, 10,788,000 Btu for process energy, and 612,000 Btu for transportation energy.
 A flow diagram of this process is shown in Figure  1 and on page A-15 in Life Cycle Assessment
for the PC Blend 2 Aircraft Radome Depainter (Thomas and Franklin, 1996).

       The composition of paint strippers using PC are defined in U.S. Patent Nos. 5,575,859
 and 5,629,277. Patent No. 5,281,723, titled Propylene Carbonate Recovery Process, describes a
 method devised to recover a cyclic alkylene carbonate, such as PC, from an effluent stream of
 carbonate, water, and polymeric solids.  The effluent would be typically processed using a
 method in which the cyclic alkylene carbonate removes an organic photoresist material from a
 substrate.

 2.2    Use

       The properties of PC make it suitable for use in painting and depainting and other
 industrial stripping and cleaning operations and as  a chemical reagent.  This section contains
 summaries of case studies conducted using PC in painting and depainting operations, as well as
 in other applications that entailed similar exposure scenarios to the painting and depainting
 operations. Complete case studies are provided in  Appendix A. Summaries of case studies are
 provided, not the complete reports or project summaries.
                                                                                     2-2

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                                                 3

                                                 O
                                                 CO
                                                 D)



                                                1
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                                                3
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Pollution Prevention Demonstration and Evaluation of Paint Application Equipment and
Alternatives to Methylene Chloride and Methyl Ethyl Ketone (J.M. Elion et al, EPA/600/SR-
96/117, October 1996).

       This research provides results of a demonstration of PC as a possible alternative to MEK.
The demonstration was conducted at the Marine Corps Logistics Base in Albany, GA.  Activities
involving the cleaning of paint application equipment with MEK were selected to demonstrate
possible PC substitution. For this demonstration, a blend of 40 percent PC and 60 percent benzyl
alcohol (BA), by weight, was chosen to replace MEK. This choice was based on the results of
laboratory screening, materials compatibility, and paint removal efficiency tests.  Based on the
demonstration, PC/B A cleaned green CARCs from the pumps as well as MEK, and it cleaned
epoxy primers better than MEK. If employed, this substitution would potentially reduce
hazardous air pollutants (HAPs) at the base by 21 percent from 1992 levels.  Although no capital
investment was required, the cost for the PC/B A blend was higher than for MEK, but the higher
cost may be offset by cleaner recovery and reclamation and further waste reduction.

Substitutes for Methylene Chloride Paint Strippers—Performance Evaluation and Adaptation
to Aircraft Maintenance Procedures (G.E. Baker and E.F. Hollins, Pacific Environmental
Services, Inc., Presented at the Air & Waste Management Association's 9tfh Annual Meeting
& Exhibition, June 8-13,1997, Toronto, Ontario, Canada).

       The pollution prevention division of the Oklahoma City Air Logistics Center at Tinker
Air Force Base (TAFB), an Air Force Material Command (AFMC) installation, investigated
possible PC blends to eliminate the use of methylene chloride-based strippers from its depainting
operations. As part of the study, bench- and full-scale tests were conducted. None of the PC
blends passed the consistency or flow tests based upon visual observation of surface wetting and
filming properties. Flash points for all but one of the blends were below 200 °F. One blend
failed the corrosion tests on magnesium.

Project Summary Life Cycle Assessment for PC Blend 2 Aircraft Radome Depainter (R.
Thomas and W.E. Franklin, EPA/600/SR-96/094, September 1996).

       The purpose of this research effort was to conduct an LCA on a potential replacement
solvent blend, PC Blend 2 (PC2), for aircraft radome depainting at the Oklahoma City Air
Logistics Center at TAFB.  PC2 is comprised of 50/25/25 weight percent N-methylpyrrolidone
(NMP), dibasic ester (DBE), and PC. The study was designed to conduct the LCA with respect
to energy requirements, solid wastes, atmospheric emissions, and waterborne wastes associated
with and resulting from the production, use, and disposal of PC2 depainting solvent. Mention of
this case study here provides the reader with information concerning an LCA conducted on a PC
blend.
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Project Summary Radome Depainting Evaluation at Tinker Air Force Base (EPA/600/SR-
95/079, June 1995).

       This research describes a test program to determine the feasibility of using 10 possible
alternative paint-stripping solvents, 5 of which were PC blends, that were less hazardous to the
environment and public health than MEK.  Testing involved immersing a 2- by 2-in square of an
aircraft radome (a fiberglass and epoxy or polyester composite material, in a honeycomb
structure) coated with a primer, a polyurethane rain-erosion coating, and a polyurethane antistatic
topcoat, in a beaker of the selected solvent. Parameters evaluated included a visual assessment of
the degree of attack (percent removal) on the coating in 0.5-, 1-, 2-, 4-, 8-, and 24-h increments.

       Test results indicated that several of the solvents stripped the paint quicker and more
efficiently than MEK.  Although visual examination showed no damage to the substrate, there
was some concern about potential substrate damage due to the complete and aggressive removal
of all three coats.  Three of the solvent PC blends completely removed the top two coats while
leaving the primer untouched. Leaving the primer layer intact is considered a suitable alternative
to complete paint removal. This process would ensure that the substrate is not damaged during
the depainting operation.  Additionally, it may provide some economic advantages in material
and manpower savings.

Project Summary Evaluation ofPropylene Carbonate in Air Logistics Center (ALC)
Depainting Operations (S. Rosenthal and A.M. Hooper, Foster Wheeler Enviresponse, Inc.,
Edison, NJ, EPA/600/SR-94/176, September 1994).

       This report summarizes a two-phase, laboratory-scale screening study evaluating
depainting solvent blends of PC as possible replacements for MEK in aircraft radome depainting
operations. The first phase of screening evaluated the performance of solvent blends from
Texaco Chemical Company containing varying percentages of PC, NMP, DBE, and other organic
solvents. Performance was compared to that of MEK based on paint removal time and visual
estimation of the amount of paint removed without any visible substrate damage. The best
performing blend was PC2, containing 25/50/25 percent PC/NMP/DBE.

       This solvent blend was then compared with MEK during the second phase of testing to
measure paint removal time and efficiency, paint adhesion, flexural properties,  weight change of
the substrate after paint removal, and hardness of the unpainted substrate test panels. Results
showed that PC2 performed favorably in comparison with MEK in removing paint from
fiberglass and epoxy test panels and in subsequent paint adhesion tests, despite a possible
indication of substrate damage.
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                                3.0 Impact Categories

       A life cycle evaluation of the potential impacts of PC requires that impacts both to the
 environment and to human health be considered. To assist in guiding the search for information
 related to PC, impact categories and subcategories were established.  Numerous impact
 categories have been proposed for life cycle impact assessment, and most LCAs to date have
 selected from these previous efforts in lieu of defining their own impact categories. However,
 impact categories are typically selected so that the goals of the study may be satisfied.

       This section lists the categories and subcategories of impacts to the environment and to
 human health that were selected as starting points for the evaluation of PC.  For each category
 and subcategory, quantitative and qualitative impact information was searched for and compiled
 under each category as appropriate. Any additional impacts found that were not part of the
 original listing were subsequently added.

 3.1    Ecological Impacts

       Potential ecological impacts of PC as used in painting and depainting operations result
 primarily from the production, use, and disposal stages of its life cycle, where emissions are
 released directly into the environment. Examples of activities that might result in environmental
 impacts could include the extraction and processing of natural gas, the volatilization of PC
 during use, or the leaching of residual PC into the soil or ground water. To establish a baseline
 set of ecological impact categories for this research, LCA guidance documents and case studies
 were consulted.  The resulting list of impact categories is shown in Table 3-1. The impacts have
 been categorized by their mechanism of action, mainly whether they result from chemical or
 nonchemical pollutants or from resource depletion.

 3.2    Human Health Impacts

       Potential human health impacts of PC as used in painting and depainting operations result
primarily from the use stage of its life cycle, where workers may be directly exposed to PC
emissions. Additional human health impacts may result from emissions released during the
production and disposal stages of the life cycle.  To establish a baseline set of human health
impact categories for this research, LCA guidance documents and case studies were consulted.
The resulting list of impact categories is shown in Table 3-2.  The impacts have been categorized
by their mechanism of action, mainly whether they result from chemical or nonchemical
pollutants.
                                                                                     3-1

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Table 3-1. Ecological Impact Categories Related to Chemical And Nonchemical Stressors
           and Resource Depletion
          Chemical
         Nonchemical
   Resource Depletion
   Global warming
   Ozone depletion
   Acid deposition
   Photochemical oxidant
   formation
   Tropospheric ozone
   Aquatic toxicity
   Eutrophication
   Visibility alterations
   pH alterations
   Chemical/biological
   content alteration
   Oxygen depletion
   Aquifer contamination
   Land use
• Ionizing radiation
• Heat
• Noise
• Environmental disturbance
      -habitat alteration
      -physical change to water
      -physical change to soil
• Regional climate change
• Species change
      -composition
      -total diversity
Nonrenewable

• Fossil fuels
• Minerals

Renewable

• Water
• Renewable energy
• Agricultural resources
• Wilderness resources
Table 3-2. Human Health Impact Categories Related to Chemical and Nonchemical
           Stressors
                   Chemical
                               Nonchemical
   Human carcinogen
   Inhalation toxicity
   Irritant (eye, lung, skin, gastrointestinal [Gl])
   Respiratory system effects
   Central nervous system effects
   Mutagenicity
   Developmental toxicity
   Allergenicity
   Blood dyscrasias
   Odors
   Cardiovascular system effects
   Reproductive effects
   Behavioral effects
   Bone effects
   Renal effects
                    Heat
                    Noise
                    Light
                    Nuisance
                                                                                   3-2

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                                   4.0 Data Review
       A joint literature search was conducted for PC and NMP. Both of these chemicals are
components of PC2, which is used in depainting. This section discusses the literature search and
summarizes the available information on PC's physical and chemical properties, environmental
fate and transport, and toxicity. However, Tables 4-1 and 4-2 are inclusive of both NMP and PC.
4.1    Sources
       Research Triangle Institute (RTF) conducted an extensive literature search for NMP and
PC. In addition to searching online databases, manufacturers were contacted, government reports
were located, and an Internet search was conducted.  Results of the literature and Internet
searches  are summarized in the following sections.
4.1.1  Literature Search
       A literature search was performed using the databases listed in Table 4-1. The databases
were searched from 1990 to the present using N-methylene-pyrrolidone and propylene carbonate
as key words.  The number of relevant articles found in each database are listed in Table 4-1.
Table 4-1. Literature Search for NMP And PC
     Name of Database
     Database Topic
Number of Articles
      Found
        MEDLDSTE
        Enviroline
 Wilson Applied Science and
    Technology Abstracts
     Pollution Abstracts
 Environmental Bibliography
  NTIS: National Technical
    Information Services
       Ei Compendex
   World Surface Coatings
         Abstracts
    Health and medicine
   Environmental subjects
   Science and technology

      Pollution topics
   Environmental subjects
Government technical reports

       Engineering
    Coating, paints, inks
        6
        1
        54

        1
        6
        2

        86
        14
                                                                                      4-1

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       A second search was performed using the following key words related to NMP and PC:
greenhouse, global warming, acid rain, smog, photochemical, ozone, air dispersion, air aging, air
transport, aquatic, plant life, eutrophication, visibility, weather, thermal, alterations, oxygen
depletion, aquifer, thermal change, and oxygen depletion. Table 4-2 lists the databases searched,
the dates searched, and the number of articles found in each database.
Table 4-2. Specific Topic Literature Search for NMP and PC
     Name of Database
   Database Topic
  Number of
Articles Found
  Dates Searched
     Meteorological and
 Geoastrophysical Abstracts
        Enviroline
        GeoArchive
       WATERNET
 Water Resources Abstracts
        GEOBASE
          BIOSIS
    Aquatic Sciences and
     Fisheries Abstracts
 Environmental Bibliography
        MEDLINE
       CANCERL1T
        PsycINFO
        TOXLINE
        EMBASE
  IAC Health and Wellness
         Database
  Meteorological and
environmental subjects
Environmental subjects
     Geosciences
     Water topics
 Water resource topics
      Ecology
  Biological abstracts
Marine and freshwater
    environments
Environmental subjects
  Health and medicine
       Cancer
  Pyschology, health
lexicological literature
 Biomedical literature
       Health
      0

      2
      0
      0
      8
      0
      22
      0

      6
      14
      3
      0
      34
      49
      1
  June 1970-1997

 August 1975-1997
 August 1974-1997
     1971-1997
 August 1967-1997
 August 1980-1997
September 1969-1997
September 1979-1997

 October 1974-1997
November 1966-1997
September 1975-1997
 October 1967-1997
 August 1965-1997
 August 1974-1997
     1976-1997
       The EPA Office of Pollution Prevention and Toxics (OPPT) provided the following
reports relevant to PC:
       •      Initial Screening of Chemical Ingredients and Substitutes in Consumer and Small
              Shop Paint Stripper Formulations.
                                                                                     4-2

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       •       Consumer/Small Shop Paint Stripping Use Cluster AR-161 Risk Management
              Report Public Comment Draft.

       The U.S. Coast Guard is currently evaluating alternatives to using methylene chloride for
small aircraft paint stripping in a Design for the Environment project.  No information on PC was
available at the time of publication.

       Huntsman Specialty Chemical in Houston, TX, was contacted for information. Because
of proprietary agreements, the names of clients could not be provided. Huntsman was able to
send the following information:

       •       Test Procedures for the Degradability and Bacterial Toxicity of Chlorinated
              Hydrocarbon Replacements (Kayser et al., n.d.).

       •       Permeability of Commercial Solvents Through Living Human Skin (Ursin et al.,
              1995).

       •       Propylene Carbonate: Toxicity Testing Summary (Huntsman, n.d.) and
              Jeffsol™ Ethylene and Propylene Carbonates (Huntsman, 1994).

4.1.2  Internet Search

       Several Internet searches were conducted to gather environmental profile  data for PC.
The following keywords were used for the searches: methylene1 chloride substitution, methyl
ethyl ketone substitution, propylene carbonate, solvent replacement, solvent substitution,
depainting solvents, painting solvents, aircraft depainting, paint removal, health effects
(propylene carbonate), environmental effects (propylene carbonate), ecological effects (propylene
carbonate), radome depainting, paint stripping, toxicity (propylene carbonate), aerospace
painting, and aerospace depainting.  Table 4-3 lists the Internet sites that were found for PC.

4.2    Physical and Chemical Properties

       Propylene carbonate is a near odorless and colorless solvent. It has  a high dielectric
constant, low vapor pressure, high chemical stability, and low viscosity. Its molecular formula is
C4H6O3.  PC has a high boiling point and a low coefficient of friction (Clark et al., n.d.).
Table 4-4 presents the physical and chemical properties of PC.
                                                                                      4-3

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Table 4-3. Internet Searches for PC Environmental Profile Data
Title
Address
                                                                          Type of Information
Chemfinder
http://chemfinder.camsoft.com
National Center for Manufacturing  http://solvdb.ncms.org
Sciences
University of Utah Material Safety  http://www.chem.utah.cdu/MSDS/P/
Data Sheet (MSDS) Archive        PROPYLENE_CARBONATE
Solvent Handbook Database       http://wastenot.inel.gov/shds/product_l/3.html
System-Product Data for
ARCONATE 1000 PROPYLENE
CARBONATE

Chemical Sampling Information    http://www.osha- slc.gov/ChemSamp_data/
                                CH_264450.html

National Institute of Standards and  http://webbook.nist.gov/chemistry
Technology (NIST) Chemistry
WcbBook

Welcome to Fisher Scientific      http://www.fisherl .com/fb/itv?2..f97.4.f
                                sc95_21.655.1...
Physical and chemical
properties

Physical and chemical
properties, health and safety
data, regulatory information,
environmental fate data

Physical and chemical
properties, toxicity data,
reactivity data

Physical and chemical
properties
                                          Physical and chemical
                                          properties

                                          Thermochemical and
                                          thermophysical properties
The Environmental Chemicals
Data Information Network
(ECDIN) Data Bank
http://ulisse.etoit.eudra.org/cgibin_ecd/
inter_query
National Fire Protection           http://www.orcbs.msu.edu/chemical/
Association (NFPA) Chemical     nfpa/hazardinformation(p-r).htrnl
Hazard Labels

Environmental Health Perspectives http://ehpnetl.niehs.nih.gov/docs/
Search Form                     ehp_search.html
Physical and chemical
properties, hazards
identification, lexicological
information, regulatory
information

Identification, physical and
chemical properties,
production and use,
legislation and rales,
occupational health and
safety, toxicity,
concentrations and fate in the
environment, detection
methods, hazards and
emergency response

Populations at risk (workers)
                                          Toxicity
                                                                                          (continued)
                                                                                                  4-4

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Table 4-3.  (Continued)
Title
Address
Type of Information
Environmental Science Center      http://esc.syrres.com/~ESC/database.htm
Experimental Log P (octanol/water
partition coefficient) Database
Physical Properties Database
(PHYSPROP)

Environmental Fate Database
(EFDB)
Commercially available database


Commercially available database
Toxic Substances Control Act Test Commercially available database
Submission (TSCATS) Database
Chemical Pointer File
Commercially available database
Compilation of Ozone Depletion   http://esc.syrres.com/~ESC/ODPGWP.htm
Potentials (ODP) and Global
Warming Potentials (GWP)

Atmospheric Oxidation Database   http://esc.syrres.com/~ESC/aopexp.htm

DefenseLESTK (Links to Army, Air http://www.defenselinfc.mil
Force, Navy, and Marine Corps
homepages)	__^^
Experimental log p
(octanol/water partition
coefficient)

Chemical structures, names,
and physical properties

Environmental fate and
exposure data including
adsorption, bioconcentration,
biodegradation, dissociation
constant, effluent
concentrations, monitoring,
occupational concentrations,
and photo-oxidation

Unpublished technical
reports submitted by industry
concerning health effects,
environmental effects, and
environmental fate

Regulatory information,
toxicity, environmental fate
and transport

N/A
                                          N/A

                                          N/A
N/A = No information was available for PC at this site.
                                                                                                  4-5

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Table 4-4. PC Physical and Chemical Properties
Physical State
Liquid
Appearance"
Odor8
Boiling point15 (°C, 760 mmHg)
Coefficient of expansion, cm3/cm3/°C
Density, Ib/gal
Dielectric constant, esu
Dipole moment, 40 °C, debye units
Evaporation rate (n-BuAc =1)
Fire point, °F
Flash point, °F
Freezing point, °C
Hansen solubility parameters, cal1/2cm"3/2
Heat capacity, cal/g/°C
Heat of combustion, cal/g

Heat of fusion, cal/g
Heat of vaporization, cal/mol
Molecular weight
Pour point, °F
Refractive index
Specific gravity
Clear colorless liquid
Slight odor
241.9
0.00096
10.05 (20 °C)
65.0 (25 °C)
62.5 (36 °C)
56.9 (40 °C)
4.98
<0.01
280
275
-49.2
13.3, Total
9.8, Dispersive (nonpolar)
8.8, Polar
2.0, Hydrogen bonding
0.389 (15 °C)
0.408 (50 °C)
0.434 (100 °C)
0.460 (150 °C)
3,396
347 (kcal/mol)
18
17,700 (50 °C)
15,200 (100 °C)
13,300 (150 °C)
12,000 (200 °C)
102.9
-100
1.4210(n20D)
1.2057 (20/4 °C)
                                                                           (continued)

                                                                                    4-6

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Physical State
Liquid
Thermal conductivity, 41 °C
Viscosity, cs
Specific gravity0
Viscosity (cP)°
Vapor pressure (mmHg)c
Surface tension (dynes-cm2)0
Hash point (Fahrenheit)0
Explosion limit % (Upper)"
Explosion limit % (Lower)a
Evaporation rate (BuAc = l)c
Solubility (water, % weight/
Typical pHd
Autoignition temperature (Fahrenheit)a
Reactivity
0.12 Btu/(hr)(ft2)(°F/ft)
49.6 x 10-5 cal/(s)(cm2)(°C/cm)
33.5 (-40 °C)
10.5 (-20 °C)
4.8 (0°C)
2.8(20°C)
1,9 (40 °C)
1.1951
2.530
1.2
41.39
269.6
14.3
1.8
0.005
Moderate (1 to less than 10 percent)
5.5 to 7.5
950
Chemical stability: stable under normal
temperatures and pressures. Incompatible with
strong oxidizing agents, acids, bases, and
reducing agents.
   Fisher Scientific,  1997.
   Clark et al., n.d.
   National Center for Manufacturing Sciences, 1996.
   ARCO Chemical Company, 1995b.
4.3    Environmental Fate and Transport

       Very little information concerning the environmental fate and transport of PC was found.
ARCO (1995a) provided a summary of the mobility, degradability, and bioaccumulation of PC as
follows:  "leaching to water may occur; however, no data were  available on soil to air or water to
air mobility." Based on the available physical and chemical properties, evaporation from soil and
water would be slow. PC may decompose in aqueous solutions that vary from a neutral pH and
in water with the transient formation of propylene oxide.  No data were available on
bioaccumulation or biomagnification (ARCO, 1995a).
                                                                                     4-7

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        Propylene carbonate was studied to determine its aerobic degradability and bacterial
toxicity (Kayser et al., n.d.). Concentrations of 250 mg/L and 2,500 mg/L were selected based on
typical concentrations detected in wastewater. Propylene carbonate was degraded over the entire
range of test concentrations, achieving 80 percent degradation 10 days after an initial lag phase of
1 day. The authors concluded that PC could be considered as being very readily biodegradable.

       Nevertheless, a patented method of transforming alkylene carbonates, such as PC, into
more environmentally manageable end products is described in Chemical Pre-Treatment and
Biological Destruction of Propylene Carbonate Waste Streams Effluent Streams to Reduce the
Biological Oxygen Demand Thereof (U.S. Patent No. 5,275,734). The invention was specifically
designed for treatment of PC used as a developer and as a stripping solvent for photoresist
materials. The effluent stream is treated to a hydrolyze PC to a relatively biodegradable
intermediate (i.e., propylene glycol), which can then be biodegraded (Shurtleff and Linger, 1994).

4.4    Toxicity

       The toxicity of PC has not been extensively studied. Huntsman (n.d.) prepared a toxicity
testing summary in an unpublished report, and another source concluded that PC was safe to use
as a cosmetic ingredient at concentrations up to 20 percent  (Final Report on the Safety
Assessment, 1987).  The MSDS sheet identifies skin, eye, and respiratory irritation as possible
toxic effects and indicates that no signs or symptoms are expected following ingestion (ARCO,
1995b). The available toxicity data are reviewed below.

       PC is also blended with other chemicals to form other depainting formulations. One  of
these is PC Blend 2, which consists of 25 percent PC, 50 percent NMP, and 25 percent DBE.
DBE includes dimethyl adipate, dimethyl succinate, and dimethyl glutarate.

       A separate environmental profile was completed for NMP as part of this project (RTI,
1998). In general NMP has a low order of acute and chronic toxicity; however, it is a skin and
eye irritant and is  well absorbed through the skin. NMP is not likely to be carcinogenic or
mutagenic but has caused reproductive and developmental effects in laboratory rats exposed to
relatively high concentrations through skin application or inhalation.

       Very little toxicity data are available for the DBE chemicals. Like NMP, dimethyl adipate
is an irritant and a reproductive/developmental toxicant in laboratory rats (U.S. EPA, 1996).
According to the MSDS for dimethyl adipate and dimethyl  succinate, these chemicals are
combustible and are incompatible with acids, bases, oxidizing agents, or reducing agents.
Combustion and decomposition products include carbon monoxide and carbon dioxide.

4.4.1  Human Data

Final Report on the Safety Assessment of Propylene Carbonate, 1987.
                                                                                     4-8

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        A number of clinical studies were conducted in hundreds of human volunteers to test
 whether or not PC and PC-containing cosmetic preparations (underarm stick, cream blush, gels,
 eyeliner, lipslicker, etc.) caused skin irritation or sensitization.  Undiluted PC caused moderate
 skin irritation, aqueous solutions containing 5 to 10 percent PC caused no irritation or
 sensitization, and cosmetic products containing 0.54 to 20 percent PC were essentially
 nonsensitizing but caused some skin irritation.  One product containing 20 percent PC appeared
 to produce a low-level photoallergic reaction in 1 of 25 people tested.

 Huntsman, 1994. JEFF SOL™ Ethylene and Propylene Carbonates.

       Dermal patch testing in humans using 5 percent and 10 percent aqueous solutions of
 JEFFSOL PC did not produce irritation or sensitization.

 4.4.2  Laboratory Animal Data

 Huntsman, n.d..  Propylene Carbonate: Toxicity Testing Summary.

       Huntsman prepared a summary of studies investigating PC's teratogenicity, subchronic
 oral and inhalation toxicity, neurotoxicity, and dermal carcinogenicity.

       Teratogenicity: Twenty-seven dams (Sprague-Dawley rats) per group were orally
 exposed by gavage to 1,000, 3,000, and 5,000 mg/kg/d of PC on days 6 through 15 of gestation.
 A control group was given deionized water.  The study was terminated on day 20 of gestation
 with a complete examination of the uterine contents. It was found that exposure to PC at
 concentrations up to 5,000 mg/kg/d did not induce developmental toxicity; however, some
 maternal toxicity was observed in the high-dose group (decreased body weight gain and food
 consumption).

       Subchronic (90-dav) Oral Toxicitv: Sprague-Dawley rats were given  1,000, 3,000, and
 5,000 mg/kg/d of PC by gavage for 90 days.  A control group was given deionized water.  In
 addition, a high-dose recovery group was included to determine the persistence and reversibility
 of any toxic effects. The recovery group was followed from day 90 of the study through day 118.
 Thirty rats per group (15 of each sex) and 20 rats in the recovery group were studied. An interim
 sacrifice of 10 rats per group, excluding the recovery group, was conducted on day 30. At
 sacrifice, all animals were necropsied and grossly examined. Blood samples were collected for
clinical chemistry and hematology measurements, and an ophthalmological examination was
performed. A full screen of potential target organ tissues was fixed for histopathological
examination. No consistent dose-related findings were reported following necropsy or
histopathological examination. Results of the test showed that PC at concentrations of up to
5,000 mg/kg/d did not induce any significant toxic effects.

       Subchronic (90-davVInhalation Toxicitv: Fischer 344/CDF rats were exposed to 100, 500,
or 1,000 mg/m3/d of aerosol PC over a 90-day period. Negative controls were exposed to filtered
                                                                                    4-9

-------
air on the same exposure regimen. Groups consisted of 30 rats (15 per sex) with an additional 20
animals per group to study acute neurotoxicity (see below). Hematology, clinical chemistry, and
urinalysis were normal in all test groups. No other significant signs of toxicity were noted, with
the exception of some periocular swelling in the high- and mid-dose groups. No systemic
toxicity was reported.

       Neurotoxicity: An additional 20 rats per group were studied concurrently with the
subchronic inhalation study to investigate acute and subchronic neurotoxicity. For the acute
study, rats received a single 6-hour exposure to PC aerosol. Observation at 1 hour and at 24
hours after exposure revealed that PC concentrations of 1,000 mg/m3 or less do not produce
behavioral alterations in rats. In addition, standard neurobehavioral tests and motor activity were
examined in groups of rats following 6 and 13 weeks of exposure. No behavioral alterations
were noted in any exposure group.

       Dermal Carcinogenicitv: Fifty microliters (uL) of undiluted PC was applied twice a
week to the shaved backs of 50 male mice for 104 weeks. Negative controls included nontreated
animals and animals treated with mineral oil; positive controls included animals treated with 0.05
percent benzo(a)pyrene in acetone. A total of 10.4 mL PC was applied to each animal over the
course of the study. No test-related deaths were observed during the course of the study. No
consistent body weight changes, tumors, or significant dermal effects were noted during the
course of the study.

Final Report on the Safety Assessment ofPropylene Carbonate, 1987.

        This report summarized laboratory animal data on acute toxicity, skin and eye irritation,
acute and subchronic dermal toxicity,  inhalation toxicity, and mutagenicity. Propylene
carbonate is typically used at concentrations ranging from <0.1 percent to 5.0 percent in
cosmetics. Various studies were conducted to assess the safety of PC use in cosmetics.  Acute
oral toxicity has been studied in rats by giving test animals single doses of undiluted PC and
cosmetic formulations dissolved in corn oil or mineral oil.  In most cases, animals were observed
for 14 days following exposure. These tests indicate a low order of acute oral toxicity, with a
reported lethal dose, 50 percent kill (LD50) in rats of 29.1 g/kg. A few animals receiving cosmetic
preparations at 5 g/kg PC exhibited some signs of toxicity (sedation, dyspnea, poor grooming,
red stools, weight loss, congested kidneys, and GI symptoms).

        Undiluted PC produced minimal to moderate ocular irritation and slight skin irritation in
Studies with rabbits. Rabbits treated with 2 mg/kg of undiluted PC on abraded skin experienced
slight erythema; however, no lesions were observed at necropsy.  In oral toxicity testing,
salivation  was noted in rats  given undiluted PC in a single 5-g/kg oral dose.  Undiluted PC was
nontoxic to dogs and guinea pigs by inhalation but caused rhinorrhea and diarrhea in rats. Daily
application of 10.5 or 17.5 percent PC in physiological saline to the skin of rats for 1 month
produced hyperkeratosis and an increase in the number of basal epithelial cells at the treatment
site. Mutagenicity was tested with several strains of Salmonella typhimurium (Ames assay) with
                                                                                      4-10

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 and without metabolic activation and in rat hepatocytes. These tests indicate that PC is not
 mutagenic. On the basis of these data, PC was determined to be a safe cosmetic ingredient in
 present concentrations and practices of use.

 Huntsman, 1994. JEFFSOL™ Ethylene andPropylene Carbonates.

       According to Huntsman, JEFFSOL PC was found to be practically npntoxic by single oral
 or dermal exposures.  Acute studies showed JEFFSOL PC to be minimally irritating to the skin
 of rabbits, while the application of the undiluted product to their eyes resulted in marked
 irritation of conjunctival tissues within 24 hours after administration. This irritation subsided
 after 48 hours in most animals. Dermal sensitization studies using guinea pigs were negative.  In
 a subchronic toxicity study, rats exposed to JEFFSOL PC at aerosol concentrations of up to 1,000
 mg/m3 over 90 days showed signs of ocular irritation only.  In a chronic study conducted over  a
 2-year period, PC was applied dermally two times a week to mice without removing the material
 between applications. The results indicate that the product is not dermally carcinogenic and
 produced no evidence of any abnormal dermal lesions or systemic toxicity from the exposure.  In
 a developmental toxicity study, pregnant rats were given oral doses of PC with concentrations up
 to 5,000 mg/kg/d over the period of fetal development.  Evidence of maternal toxicity was
 apparent in the high-dose group; however, there were no significant findings with regard to
 fertility parameters, viable and nonviable fetuses, fetal sex distribution, or fetal body weights. In
 addition, no fetal malformations were observed. On the basis of these studies, Huntsman
 concluded that PC would not cause serious injury from amounts that might be accidentally
 ingested, spilled on the skin, or inhaled.

 4.4.3  Toxicokinetics

       No information was found on the distribution, metabolism, and excretion of PC. One
 study was found that investigated dermal absorption.

 Ursin et at, 1995. Permeability of Commercial Solvents Through Living Human Skin.

       A procedure to measure the steady-state rate of permeation of commercial solvents
through living human skin was used on human female skin. The skin was removed from healthy
females during plastic surgery of the breast. The samples were thinned by removing the dermal
tissue from the epidermis and then stretched to a thickness of 300 to 600 /on. Each piece of
surgically removed skin usually provided sufficient material to run nine permeation experiments.
The permeability rate of PC was determined to be 0.7 g/m2h compared to a permeability rate for
water of 24 g/m2h. Therefore, it can be concluded that PC is not readily absorbed through the
skin.
                                                                                   4-11

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                               5.0 Impact Assessment
       No specific data were available regarding environmental impacts of PC releases. The
U.S. EPA (1996) has prepared an LCA of PC2 (a mixture of 50 percent NMP, 25 percent DBE,
and 25 percent PC).

5.1    Human Populations at Risk

       U.S. EPA (1996) reported that air emissions from PC2 would not be expected to pose a
hazard to workers or nearby residents based on comparison of modeled air concentrations to
recommended occupational standards. A safety assessment conducted for PC because of its use
in various cosmetic products concluded that PC-containing cosmetics posed little hazard. Based
on the low order of toxicity, low rate of skin absorption, low volatility, and low environmental
persistence, PC poses minimal risk to workers and residential populations.

5.2    Natural Resources/Ecosystems

       The LC50 values for the following species have been determined (ARCO Chemical
Company, 1995b):

       1.     Lepomis Macrochirus — >5 mg/L (24 hours)
       2.     Goldfish - >5 mg/L (24 hours)
       3.     Trout - >5 mg/L (24 hours).

       No relevant data have been identified for soil organisms or plants and terrestrial animals
(ARCO Chemical Company, 1995a). The urban ozone formation potential for PC (C2H4 = 1) is
0.08 (National Center for Manufacturing Sciences, n.d.).

       Of the list of ecological impact categories presented in  Section 3.1, limited data were
available for PC's aquatic toxicity and ozone formation potential.  Data needs include
information concerning its global warming potential, visibility alterations, weather alterations,
pH alterations, chemical/biological content alterations, aquifer contamination, land use, and
natural resource depletion.
                                                                                   5-1

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                            6.0 Environmental Regulations

        The Chemical Abstracts Service (CAS) number for PC is 108-32-7.  Propylene carbonate
 is listed in the Toxic Substances Control Act (TSCA) Inventory.  Propylene carbonate is not
 classified in the Department of Transportation's (DOT's) hazard class system (Clark et al., n.d.).
 Table 6-1 summarizes regulatory information for PC.
 Table 6-1. Regulatory Information for PC
  Regulation
                                                                      Applicability to PC
  Clean Air Act

  Comprehensive Environmental Response, Compensation, and Liability Act
  Resource Conservation and Recovery Act

  Superfund Amendments and Reauthorization Act

  Clean Water Act

  Occupational Safety and Health Administration

  American Conference of Governmental and Industrial Hygienists

  International Agency for Research on Cancer

  National Institute for Occupational Safety and Health
  National Toxicology Program	

       In addition, PC has a National Fire Protection Association (NFPA) health hazard rating of
1 (NFPA, n.d.). This rating includes materials that may cause irritation on exposure but only
minor residual injury even if no treatment is given, including those that require use of an
approved canister-type gas mask. Propylene carbonate has an NFPA flammability rating of 1.
This rating includes materials that must be preheated before ignition can occur. These materials
require significant preheating  under all ambient temperature conditions before ignition and
combustion occur. Propylene carbonate has an NFPA reactivity rating of 0, meaning that the
solvent is normally stable even under fire exposure conditions and does not react with water.
Not listed

Not listed

Not listed

Not listed

Not listed

Not listed

Not listed

Not listed

Not listed

Not listed
                                                                                     6-1

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                                     7.0 Summary

        Propylene carbonate is an odorless, clear liquid that has a variety of commercial uses,
 including as an ingredient in cosmetics, as an extraction solvent, as an electrochemistry solvent,
 as a plasticizer, as an adhesive in food packaging, and in depainting.  PC and various PC blends'
 are under consideration as replacement solvents for MEK and methylene chloride in depainting
 operations. This report reviewed the available data regarding the performance of PC blends in
 depainting operations, their potential health hazards, and their potential environmental impacts.

        Very little information on the environmental fate and transport of PC is available;
 however, based on its moderate water solubility and low vapor pressure, PC spilled onto'soil
 could leach into ground water but would only be slowly released into the air. At least one study
 indicates that PC biodegrades fairly rapidly (up to 80 percent in 10 days) in domestic wastewater.

       The available toxicity data indicate that PC is a mild skin and eye irritant with low acute,
 subchronic, and chronic toxicity. It is not known to be a reproductive toxin, a mutagen, or a
 carcinogen. Data compiled from hundreds of human volunteers exposed dermally to undiluted
 PC and various cosmetic formulations indicate that it is safe for cosmetic use.  Worker exposures
 to PC during its manufacture or use are limited because of its low volatility and low skin
 permeation rate; however, repeated skin exposure can cause irritation.

       The aquatic toxicity of PC is low.  This finding, combined with an expected low
persistence and bioaccumulation potential, indicate that environmental impacts of PC should be
low.
                                                                                     7-1

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                                   8.0  References
 ARCO Chemical Company.  1995a. Propylene Carbonate: Ecological Information.
    Manufacturer's unpublished report.

 ARCO Chemical Company.  1995b. Arconate® 1000 Propylene Carbonate. Material Safety
    Data Sheet.


 Bantu, N.R., et al. January 25, 1994. Propylene Carbonate Recovery Process.  U.S. Patent No
    5,281,723.


 Clark, R.S., D.L. Green, M.T. Buttram, R. Lawson, and G.J. Rohwein. n.d.  Studies on the Use
    of Propylene Carbonate as a High-Voltage Insulator.  Sandia National Laboratories,
    Albuquerque, NM, under USDOE Contract No. DE-AC04-76DP00789.

 Elion, J.M., J. Flanagan, J.H. Turner, J.T. Hanley, and E.A. Hill. October 1996. Pollution
    Prevention Demonstration and Evaluation of Paint Application Equipment and Alternatives
    to Methylene Chloride and Methyl Ethyl Ketone. EPA/600/SR-96/117.

 [No author] 1987. Final report on the safety assessment of propylene carbonate. Journal of the
    American College of Toxicology 6(1):23-51.

Fisher Scientific. 1997. Propylene Carbonate Material Safety Data Sheet. Online. Available:
    http://www.fisherl.com/fb/itv?16..f97.4.msf0008:174.1. Accessed 19 September 1997.

Huntsman Corporation, n.d.  Propylene Carbonate: Toxicity Testing Summary. Manufacturer's
    unpublished report.

Huntsman Corporation. 1994. JEFFSOL™ Ethylene and Propylene Carbonates. Product
    report.


Kayser, G., M. Koch, W. Erlmann, and W. Ruck. n.d.  Test Procedures for the Degradability
    and Bacterial Toxicity of Chlorinated Hydrocarbon Replacements. Institute for
    Developmental Hydraulic Engineering at the University of Stuggart (Translated from
    German).
                                                                                   8-1

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National Center for Manufacturing Sciences. 1996. SOLV-DB: Propylene Carbonate.  Online.
   Available:  http://solvdb.ncms.org/ncmsenvr.idc?solvno=00108327A. Accessed 12
   September 1997.

National Fire Protection Association.  Guide to Hazard Information--(P-R).  Online. Available:
   http://www.orcbs.msu.edu/chemical/nrpa/hazardinformation(p-r).html. Accessed 19
   September 1997.

Rosenthal, S., and A.M. Hooper. September 1994. Evaluation of Propylene Carbonate in Air
   Logistics Center (ALC) Depainting.  EPA/600/R-94/176.

Shurtleff, J.A., and K.P. linger. January 4, 1994. Chemical Pre-Treatment and Biological
   Destruction of Propylene Carbonate Waste Streams Effluent Streams to Reduce the
   Biological Oxygen Demand Thereof. U.S. Patent No. 5,275,734.

Thomas, R., and W.E. Franklin. September 1996. Life Cycle Assessment for PC Blend 2
   Aircraft Radome Depainter. EPA/600/R-96/094.

Ursin, C., C.M. Hansen, J.W. Van Dyk, P.O. Jensen, I.J. Christensen, and J. Ebbehoej.  July
    1995. Permeability of commercial solvents through living human skin. Am. Ind. Hyg. Assoc.
   J. 56:651-660.

U.S. EPA.  June 1995. Radome Depainting Evaluation at Tinker Air Force Base. EPA/600/SR-
   95/079.

U.S. EPA.  1996.  Consumer/Small Shop Paint Stripping Use Cluster AR-161 Risk Management
   Report (Public comment draft). Augusts.
                                                                                   8-2

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                                     Appendix A
                     PROPYLENE CARBONATE CASE STUDIES
Depainting Case Studies

Pollution Prevention Demonstration and Evaluation of Paint Application Equipment and
Alternatives to Methylene Chloride and Methyl Ethyl Ketone
(J.M. Elion et al, EPA/600/SR-96/117, October 1996).

Introduction

This research provides results of a demonstration of PC as a possible alternative to MEK.  The
demonstration was conducted at the Marine Corps Logistics Base in Albany, GA. Activities
involved the cleaning of paint application equipment with MEK. For this demonstration, a blend
of 40 percent PC and 60 percent benzyl alcohol (B A),  by weight, was chosen to replace MEK.
This choice was based on the results of laboratory screening, materials compatibility, and paint
removal efficiency tests.  Based on the demonstration, PC/BA cleaned green CARCs from the
pumps as well as MEK, and it cleaned epoxy primers better than MEK. If employed, this
substitution would potentially reduce HAPs at the base by 21 percent from  1992 levels.

Results and Discussion

For this demonstration, a blend of PC/BA was chosen  to replace MEK for cleaning paint
application equipment such as pumps, hoses, and guns. Four 208-L barrels of this cleaner were
used as a direct replacement for MEK. No capital investment was required.

Use of the PC/BA cleaner was monitored by weighing the amount of cleaner flushed through the
system, including the amount used in the initial prewash, the final wash, and the filter wash.
Results showed that the PC/BA cleaned green CARC from the pumps as well as MEK, and it
cleaned epoxy primers from the pumps better than MEK based on the average gallons (volume)
used and the time to clean the equipment. The use of the blend lowered worker exposure to
hazardous material, reduced cleaner usage and labor time for cleaning, and significantly
decreased the downtime of the primer pumps.

The advantages of using the PC/BA blend were its lower vapor pressure, its reduction in solvent
use and labor time for cleaning, and its classification as a nonregulated hazardous waste by
RCRA. The PC/BA blend effectively removed epoxy primers better than MEK, and substitution
for MEK would potentially reduce HAPs at the Marine base by 21 percent  from 1992 levels.

The disadvantage of the PC blend was that it cost more than MEK.
                                         A-l

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Although no capital investment was required, the cost of the PC/B A blend was higher than that
of MEK, but the higher cost may be offset by cleaner recovery and reclamation and further waste
reduction.

Substitutes for Methylene Chloride Paint Strippers-Performance Evaluation and Adaptation
to Aircraft Maintenance Procedures. (G.E. Baker and E.F.  Hollins, Pacific Environmental
Services, Inc., Presented at the Air & Waste Management Association's 90th Annual Meeting
& Exhibition, June 8-13,1997, Toronto, Ontario, Canada).

Introduction

The recently promulgated National Emission Standards for Hazardous Air Pollutants  (NESHAP)
for  the aircraft industry all but require the elimination of the use of methylene chloride-based
paint strippers for the depainting of aircraft.  Consequently, the pollution prevention division of
the  Oklahoma City Logistics Center at TAFB, an AFMC installation, must investigate possible
ways to eliminate the use of methylene chloride-based strippers from its depainting operations.
More than 80 percent of the depainting operations at TAFB involve KC-135 aircraft.  The
purpose of this research was to evaluate the performance of aircraft depainting solvents that may
be used to replace the methylene chloride-based strippers.  As part of the study, bench- and full-
scale tests were conducted.

Results and Discussion

This research focused on identifying a drop-in replacement for the 19 percent phenolic-methylene
chloride paint stripper currently used at TAFB. The replacement chosen must meet several
criteria, including not being on the Toxic Release Inventory (TRI) list, being less hazardous to
workers and to the environment, producing less waste, requiring less personal protective
equipment for its use, costing less, and being usable in current spray delivery systems.

In bench-scale testing, 60 products from 30 vendors were identified that claimed to be
alternatives to methylene chloride for paint stripping, including stripping of polyurethane aircraft
primers.  Of these 60 products, 15 were selected for extensive on-site testing. These products are
listed in Table A-l.

Both analytical testing in the laboratory and on-site panel testing were conducted using tests
prescribed in TAFB's LAPE 94-10A (purchase description testing regimen) testing method and
several American Society for Testing and Materials (ASTM) tests, including ASTM D 92 (tests
for flash point), D 2196 (tests for viscosity), and F 519 (tests for corrosion and hydrogen
embrittlement). On-site  test panels were 5- by 10-in aluminum alloy panels coated with a
polysulfide primer and a polyurethane topcoat.  Three different application, removal, and
reapplication procedures were employed in these tests to examine the impacts of varying the
coating thickness, varying the time of exposure of the panel to the solvent, and applying the
                                          A-2

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 Table A-l. Listing of the Solvents Selected for Performance Evaluation
            Vendor
    Solvent name
                                                              Comments
  Huntsman Chemical
  Huntsman Chemical
  Huntsman Chemical
  Huntsman Chemical
  Huntsman Chemical
  Huntsman Chemical
  Gage Chemical
  Gage Chemical
  Gage Chemical
  Turco Products
  Turco Products
  Turco Products
  Eldorado
  Eldorado
  Eldorado
 7520-46-2T        PC blend
 7520-46-5T        PC blend
 7520-46-6T        PC blend
 7520-46-1T        PC blend
 7520-46-3T        PC blend
 7520-46-4T        PC blend
 Stingray 874        H2O2 solvent
 Stingray 880        Neutral in pH
 Stingray 894        H2O2 solvent
 6813-E             Alkaline solvent
 6840-S             Alkaline solvent
 6867               A version of 6813
 5000/3140          Two-part system, with H2O2
 5000/3170          Two-part system, with H2O2
 5000/1940          Current methylene chloride stripper
	               usedatTAFB
product according to the manufacturer's recommendations. All applications for the three
procedures were conducted by pouring solvent on the panels.
None of the Huntsman blends passed the consistency or flow tests.  Flash points for all but one of
the blends were below 200 °F.  Two of the Turco products failed the hydrogen embrittlement
tests. All of the Gage and Eldorado products failed the flash point test.
Only the Huntsman blend 2 failed the corrosion tests on magnesium. Significant corrosion of the
metal specimens occurred with all three Gage, both Eldorado, and two of the three Turco
products, again predominantly where magnesium metal was present.
                                        A-3

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The results of the Eldorado and two Gage products were the complete removal of the topcoat and
primer with only the first solvent application. Turco 6840-S also removed the paint but required
a second application to achieve greater than 95 percent primer removal. The other two Turco
products performed similarly, requiring a second application but left slightly more primer on the
surface after the second application.

Project Summary Life Cycle Assessment for PC Blend 2 Aircraft Radome Depainter; R.
Thomas and W.E. Franklin, EPA/600/SR-96/094, September 1996.

The purpose of this research effort was to conduct an LCA on a potential replacement solvent
blend, PC2, for aircraft radome depainting at the Oklahoma City Air Logistics Center at TAFB.
PC2 is comprised of 50/25/25  weight percent NMP, DBE, and PC. The study was designed to
conduct the LCA with respect to energy requirements, solid wastes, atmospheric emissions, and
waterborne wastes associated with and resulting from the production, use, and disposal of PC2
depainting solvent.

This case study provides the reader with information concerning an LCA conducted on a PC
blend.

Project Summary Radome Depainting Evaluation at Tinker Air Force Base
(EPA/600/SR-95/079, June 1995).

Introduction

This research describes a test program to determine the feasibility of using 10 possible alternative
paint-stripping solvents, 5 of which were PC blends, that were less hazardous to the environment
and public health than MEK.  Testing involved immersing a 2- by 2-in square of an aircraft
radome (a fiberglass and epoxy or polyester composite  material, in a honeycomb structure)
coated with a primer, a polyurethane rain-erosion coating, and a polyurethane antistatic topcoat,
in a beaker of the selected solvent. Parameters evaluated included a visual assessment of the
degree of attack (percent removal) on the coating in 0.5-, 1-, 2-, 4-, 8-, and 24-h increments.

Test results indicated that several of the solvents stripped the paint quicker and more efficiently
than MEK.  Although visual examination showed no damage to the substrate, there was some
concern about potential substrate damage due to the complete and aggressive removal of all three
coats. Three of the solvent PC blends completely removed the top two coats while leaving the
primer untouched. Leaving the primer layer intact is considered a suitable alternative to
complete paint removal. This process would ensure that the substrate is not damaged during the
depainting operation.  Additionally, it may provide some economic advantages in material and
manpower savings.
                                          A-4

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 Results and Discussion
 The alternative solvents evaluated, along with their approximate compositions, are shown in
 Table A-2.
Table A-2. Alternative Solvents Evaluated
 Alternative solvent:
 Approximate composition of PC/NMP/DBE, %
 Huntsman Formulation C #7210-60-1
 Huntsman Formulation D #7210-60-2
 Huntsman Formulation E #7210-60-3
 Huntsman Formulation F #7210-60-4
 Huntsman Formulation G #7210-60-5
 Commercially available solvents:
 EZE Products, Inc. 540
 EZE Products, Inc. 542
 Turco Products, Inc. 6776 Lo
 Turco Products, Inc. 6776 Thin
 Turco Products, Inc. 6813
40-60/10-30/15-35 percent PC/NMP/DBE
15-35/10-30/25-45 percent PC/NMP/DBE
15-35/40-60/ percent PC/DBE
35-55/30-50/percent PG/DBE
30-50/30-50/ percent PC/DBE

Did not contain PC, NMP, or DBE
Did not contain PC, NMP, or DBE
Did not contain PC, NMP, or DBE
Did not contain PC, NMP, or DBE
Did not contain PC, NMP, or DBE
The removal effectiveness of the solvents varied greatly. Some solvents, the EZE and Turco
products, aggressively removed all three coats.  The Huntsman formulations E, F, and G
completely removed the first two coats while leaving the primer coat intact.
The purchase cost for each of the solvents evaluated is presented in Table A-3.
The costs for the commercially available strippers are as quoted, while those of the Huntsman
formulations are calculated from the cost of the individual components multiplied by their
percentage in the final blend; no cost of blending the mixtures was included, nor was a profit
margin for the supplier of the blends.
                                         A-5

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Table A-3. Purchase Cost Comparison of Selected Solvents
 Solvent/Blend
Approximate Cost, $/gal
 MEK

 Huntsman Formulation F #7210-60-4

 Huntsman Formulation E #7210-60-3

 Huntsman Formulation G #7210-60-5

 Huntsman Formulation D #7210-60-2

 Huntsman Formulation C #7210-60-1

 EZE Products, Inc. 540

 Turco Products, Inc. 6776 Thin

 Turco Products, Inc. 6813

 Turco Products, Inc. 6776 Lo

 EZE Products, Inc. 542
         $5.00

         $9.00

         $9.00

         $9.00

        $12.00

        $12.00

        $14.00

        $17.00

        $17.00

        $17.00

        $18.00
Project Summary Evaluation ofPropylene Carbonate in Air Logistics Center (ALC)
Depainting Operations. (S. Rosenthal, AM. Hooper, Foster Wheeler Enviresponse, Inc.,
Edison, NJ. EPAJ600/SR-94/176, September 1994).

Introduction

This report summarizes a two-phase, laboratory-scale screening study evaluating depainting
solvent blends of PC as possible replacements for MEK in aircraft radome depainting operations.
The first phase of screening evaluated the performance of solvent blends from Texaco Chemical
Company containing varying percentages of PC, NMP, DBE, and other organic solvents.
Performance was compared to that of MEK based on paint removal time and visual estimation of
the amount of paint removed without any visible substrate damage. The best performing blend
was PC2, containing 25/50/25 percent PC/NMP/DBE.

This solvent blend was then compared with MEK during the second phase of testing to measure
paint removal time and efficiency, paint adhesion, flexural properties, weight change of the
substrate after paint removal, and hardness of the unpainted substrate test panels. Results
showed that PC2 performed favorably in comparison with MEK in removing paint from
fiberglass and epoxy test panels and in subsequent paint adhesion tests, despite a possible
indication of substrate damage.
                                         A-6

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Results and Discussion


Results from the evaluation tests indicated that the best performing solvent blend was PC2
Compared to MEK, this solvent had the following results:


       PC2 removed 100 percent of the paint in about the same time as MEK and required
       scraping for total removal.
                                                                                   more
       PC2 showed possible damage to the top resin layer of the fiberglass and epoxy substrate
       which will require further study.


       PC2 and MEK panels exhibited a small weight loss after immersion for 4 h.

       PC2 and MEK did not impact paint adhesion.

Recommendations from the evaluation indicate that further examination of the potential adverse
effects of the solvent on the substrate is necessary and that the issue of equipment compatibility
waste disposal practices, and procedures for removing the PC2 residue be further investigated
                                         A-7
                                                     . GOVERNMENT PRINTING OFFICE: 199* - 650.001/80201

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