United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S8-87/035 Sept. 1987
&EPA Project Summary
An Environmental Source Book on
the Photovoltaics Industry
P. D. Moskowitz, P. D. Kalb, J. C. Lee, and V. M. Fthenakis
The report gives background informa-
tion on the photovoltaics industry to
help the U.S. EPA evaluate premanu-
facture notice (PMN) and significant
new use regulation (SNUR) submittals
from the industry. It also gives informa-
tion for the photovoltaics industry on
the Toxic Substances Control Act
(TSCA) compliance requirements. This
industry uses a large diversity of toxic
and hazardous chemicals. Attention is
currently focused on such gases as
silane, phosphine, arsine, diborane, and
hydrogen selenide which may be used
in large quantities and for which there
is limited industrial experience. Most
materials used by the industry are al-
ready listed in the TSCA Inventory List.
Unlisted compounds are used as feed-
stocks or are the actual products them-
selves. Manufacturers using or pro-
ducing unlisted materials must apply to
EPA for a PMN. Some materials
(especially those defined to be acutely
toxic) contained in the Inventory List
may be used in larger quantity or in
applications which differ from current
industrial use; these are potential
candidates for SNUR.
This Project Summary was developed
by EPA's Air and Energy Engineering
Research Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that Is fully docu-
mented In a separate report of the same
title (see Project Report ordering In-
formation at back).
Introduction
This report presents background in-
formation on the photovoltaics industry
to help the U.S. EPA evaluate future
Premanufacture Notice (PMN) submittals
and the need for Significant New Use
Regulations (SNUR), implemented under
authority granted by the Toxic Substances
Control Act (TSCA).
In this context, this report:
• Gives an overview of the structure
and nature of the past, present, and
future photovoltaics industry;
• Describes the steps involved in
synthesizing and assembling photo-
voltaic cells, modules, and arrays;
• Identifies chemicals used in these
processes;
• Describes potential chemical and
physical hazards to workers in manu-
facturing facilities;
• Describes potential hazards to public
health and the environment from
routine and accidental releases from
manufacturing facilities;
• Describes occupational and environ-
mental control technology options;
and
• Discusses applicability of current
rules and regulations promulgated
under the authority of the TSCA to
potential chemical hazards in photo-
voltaic cell manufacturing facilities.
Production
In 1982, worldwide production of
photovoltaic devices was 8.4 to 9.0 MWp
(the maximum amount of power the
devices are capable of producing); of this,
4.9 to 5.5 MWp was produced by U.S.
manufacturers. This contrasts sharply
with U.S. module shipments in 1975,
estimated at 300 kWp. Corresponding in-
creases have been realized also in the
installed annual production capacity, cur-
rently estimated to be 13.1 MWP.
After a dramatic increase in production
from 5.7 to 13.1 MWp between 1982 and
1983, total U.S. photovoltaic module
shipments have declined to 11.7 and 8.6
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MWP in 1984 and 1985, respectively.
During the same period, however, world-
wide production has steadily increased
from 9.3 MWp in 1982 to 25 MWP in
1985.
Occupational Health Hazards
A large diversity of chemical and
physical agents which can present health
hazards to workers may be associated
with photovoltaic cell manufacturing pro-
cesses. In order to provide focus to the
identification of these potential hazards,
they are broken down into four categories:
explosives and flammables, corrosives
and oxidizers, poisons, and miscellaneous.
Explosive compounds are those which
can undergo and sustain chain reactions
during oxidation. Of the various com-
pounds used in photovoltaic cell manu-
facture, silane and hydrogen present the
greatest potential explosive hazards.
Flammable materials can be ignited and
sustain a flame over a range of conditions
(e.g., temperature and pressure). In photo-
voltaic cell manufacture, materials used
in relatively large quantity that present
flammability hazards include hydrogen
and methane. Of these materials, most
interest focuses on the silanes because
of the pyrophoric nature of these materials
and their relatively large scale applica-
tions.
The health effects of poisonous mate-
rials may be divided into two classes for
discussion purposes: acute poisonings
arising from short-term exposures to
relatively large concentrations of mate-
rials which may cause shock (collapse),
severe inflammation of the lungs, or even
death; and, a wide range of effects arising
from low-level sublethal exposures which
may continue over periods of months or
years.
In photovoltaic cell manufacture there
are a variety of toxic gases, liquids, and
solids that can present acute hazards to
workers who are accidently exposed to
these agents. Attention has focused on
toxic gases (e.g., arsine, diborane,
hydrogen selenide, and phosphine) be-
cause of their potential large scale use in
the photovoltaic industry and because of
their potential to expose workers in short
periods of time to high doses.
In the manufacture of thin-film photo-
voltaic cells, electrical and electromag-
netic fields generated from process equip-
ment may present occupational hazards.
Radio-frequency (rf), plasma etching,
plasma deposition, and sputtering equip-
ment, if not designed and maintained
properly, may emit nonionizing radiation
into the occupational workspace. Laser
scribing equipment may also present
electrical shock and laser beam hazards
to employees.
Environmental Releases
The quantity and type of material re-
leased to the environment from a manu-
facturing facility depend on the production
and control technology alternatives used.
Specific emission standards for the
photovoltaics industry have not yet been
set. Emission control standards developed
for related industries (e.g., the semicon-
ductor industry), however, may provide
guidelines for control technology require-
ments in the photovoltaics industry.
In these manufacturing facilities, a large
variety of materials may be used; some
may be released as by products of normal
or abnormal plant operations. Although
manufacturing facilities may produce
liquid, solid, and gaseous effluents, only
gaseous effluents are likely to present
acute hazards to public health. Liquid and
solid wastes may also present hazards,
but these can only expose the public
indirectly (i.e., drinking water and food-
chains) and over longer time periods.
Exposures via these pathways can also
be more easily monitored and controlled.
Hence liquid and solid wastes may pre-
sent chronic, but not acute, risks to public
health.
Air Emissions
At present EPA has not established
emissions standards for the routine or
accidental discharge of atmospheric pol-
lutants from the photovoltaics industry.
National Emission Standards for Hazard-
ous Air Pollutants for arsenic and cad-
mium might provide guidance to
regulators of the photovoltaics industry's
use of these materials.
Solid Wastes
Solid wastes produced in some manu-
facturing processes studied are residuals
from the deposition process or environ-
mental control systems. Some of these
wastes may be classified as hazardous
under the Hazardous and Solid Waste
Amendment Act of 1984.
Liquid Wastes
Liquid wastes may arise from wet
etching operations or from solvents used
in cleaning processes. Efforts are now
underway to eliminate wet etching opera-
tions. Consequently, attention is now
focused on the control of leaking solvents
from storage tanks (often trichloroethane).
In the semiconductor industry, under-
ground storage tanks have leaked clean-
ing solvents into the groundwater and
contaminated public water supply wells
in Silicon Valley. This problem appears to
be endemic to many semiconductor
manufacturing facilities in that region.
As a result of these leaks, many lawsuits
have been filed against some large semi-
conductor manufacturers in the industry.
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P. D. Moskowitz, P. D. Katb, J. C. Lee, and V M. Fthenakis are with Brookhaven
National Laboratory, Upton, Long Island, NY 11973
Robert C. Lagemann is the EPA Project Officer (see below).
The complete report, entitled "An Environmental Source Book on the
Photovoltaics Industry," (Order No. PB 87-224 358/AS; Cost: $13.95, subject
to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650
The EPA Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
OCT29-8/1
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Official Business
Penalty for Private Use $300
EPA/600/S8-87/035
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