U.S. Environmental Protection Agency
Hazard Characterization Document
December, 2009
Ethylene (CASRN 74-85-1)
The High Production Volume (HPV) Challenge Program1 was conceived as a voluntary
initiative aimed at developing and making publicly available screening-level health and
environmental effects information on chemicals manufactured in or imported into the United
States in quantities greater than one million pounds per year. In the Challenge Program,
producers and importers of HPV chemicals voluntarily sponsored chemicals; sponsorship
entailed the identification and initial assessment of the adequacy of existing toxicity
data/information, conducting new testing if adequate data did not exist, and making both new
and existing data and information available to the public. Each complete data submission
contains data on 18 internationally agreed to "SIDS" (Screening Information Data Set1'2)
endpoints that are screening-level indicators of potential hazards (toxicity) for humans or the
The Environmental Protection Agency's Office of Pollution Prevention and Toxics (OPPT) is
evaluating the data submitted in the HPV Challenge Program on approximately 1400 sponsored
chemicals by developing hazard characterizations (HCs). These HCs consist of an evaluation of
the quality and completeness of the data set provided in the Challenge Program submissions.
They are not intended to be definitive statements regarding the possibility of unreasonable risk of
injury to health or the environment.
The evaluation is performed according to established EPA guidance2'3 and is based primarily on
hazard data provided by sponsors; however, in preparing the hazard characterization, EPA
considered its own comments and public comments on the original submission as well as the
sponsor's responses to comments and revisions made to the submission. In order to determine
whether any new hazard information was developed since the time of the HPV submission, a
search of the following databases was made from one year prior to the date of the HPV
Challenge submission or OECD HPV submission to the present: (ChemID to locate available
data sources including Medline/PubMed, Toxline, HSDB, IRIS, NTP, ATSDR, IARC,
EXTOXNET, EPA SRS, etc.), STN/CAS online databases (Registry file for locators, ChemAbs
for toxicology data, RTECS, Merck, etc.) and Science Direct. OPPT's focus on these specific
sources is based on their being of high quality, highly relevant to hazard characterization, and
publicly available.
OPPT does not develop HCs for those HPV chemicals which have already been assessed
internationally through the HPV program of the Organization for Economic Cooperation and
Development (OECD) and for which Screening Initial Data Set (SIDS) Initial Assessment
Reports (SIAR) and SIDS Initial Assessment Profiles (SIAP) are available. These documents are
presented in an international forum that involves review and endorsement by governmental
1	U.S. EPA. High Production Volume (HPV) Challenge Program; http://www.epa.gov/chemrtk/index.htm.
2	U.S. EPA. HPV Challenge Program - Information Sources; http://www.epa.gov/chemrtk/pubs/general/guidocs.htm.
3	U.S. EPA. Risk Assessment Guidelines; http://cfpub.epa.gov/ncea/raf/rafguid.cfm.

U.S. Environmental Protection Agency
Hazard Characterization Document
December, 2009
authorities around the world. OPPT is an active participant in these meetings and accepts these
documents as reliable screening-level hazard assessments.
These hazard characterizations are technical documents intended to inform subsequent decisions
and actions by OPPT. Accordingly, the documents are not written with the goal of informing the
general public. However, they do provide a vehicle for public access to a concise assessment of
the raw technical data on HPV chemicals and provide information previously not readily
available to the public.

U.S. Environmental Protection Agency
Hazard Characterization Document
December, 2009
Chemical Abstract Service
Registry Number
Chemical Abstract Index
Structural Formula
Ethylene (CASRN 7485-1) is a gas with moderate water solubility and high vapor pressure. At a
very low temperature, it is a liquid. It is expected to have high mobility in soil. CASRN 7485-1
is expected to biodegrade in the environment. The rate of volatilization is considered high. The
rate of hydrolysis is considered negligible. The rate of atmospheric photooxidation is moderate.
An EPISuite (v4.00) estimated bioaccumulation factor of 2.0 suggests bioconcentration is low.
CASRN 7485-1 is expected to have low persistence (PI) and low bioaccumulation potential
Acute toxicity of CASRN 74-85-1 to rats is low via the inhalation route. There is no evidence to
suggest that the liquid ethylene gas is irritating to skin or eyes; however, it might cause frost
injuries. In a 13-week repeated-dose toxicity study in rats via inhalation-exposure, CASRN 74-
85-1 did not show test substance-related toxicity; the NOAEC is 10,000 ppm (11.5 mg/L). In a
combined reproductive/developmental toxicity screening test in rats via inhalation, no effects on
reproductive and developmental parameters were seen; the NOAEC is 5000 ppm (5.75 mg/L).
CASRN 74-85-1 did not induce gene mutations in an in vitro test or chromosomal aberrations in
in vitro and in vivo tests. CASRN 74-85-1 showed a equivocal evidence for carcinogenicity in
rats when exposed up to 3000 ppm (3.45 mg/L). CASRN 74-85-1 showed equivocal evidence
for carcinogenicity in animals.
The acute aquatic toxicity values for CASRN 74-85-1 from the SIDS documents are as follows:
for fish, the 96-hour LC50 (QSAR estimated) is 50-119.5 mg/L; for aquatic invertebrates, the 48-
hour EC50 (QSAR estimated) is 53-153 mg/L and for aquatic plants, the measured 72-hour EC50
values are 40 mg/L (biomass) and 72 mg/L (growth rate). EPA provided the ECOSAR predicted
values to support these data—the 96-hour LC50 for fish is 96 mg/L, the 48-hour EC50 for aquatic
invertebrates is 48.4 mg/L, and the 96-hour EC50 for aquatic plants is 16.7 mg/L.
No data gaps were identified for SIDS endpoints.	

U.S. Environmental Protection Agency
Hazard Characterization Document
December, 2009
The sponsor country, Norway, presented the SIDS documents at the OECD SIAM 5 during
October 28-30, 1996. The SIAR, SIAP and Dossier were finalized and published by the UNEP
in October 1998 (http://www.chem.unep.ch/irptc/sids/OECDSIDS/74851 .pdf). This hazard
characterization includes EPA review of the SIDS documents and relevant studies obtained
through literature search.
1.	Chemical Identity
1.1	Identification and Purity
See identification and purity information at:
http://www.chem.unep.ch/irptc/sids/OECDSIDS/74851 .pdf.
1.2	Physical-Chemical Properties
See physical-chemical properties at: http://www.chem.unep.ch/irptc/sids/OECDSIDS/74851 .pdf.
2.	General Information on Exposure
2.1	Production Volume and Use Pattern
CASRN 74-85-1 had an aggregated production and/or import volume in the United States of 1
billion pounds and greater during calendar year 2005.
Non-confidential information in the IUR indicated that the industrial processing and uses of the
chemical include intermediates, surface active agents, and other. Non-confidential commercial
and consumer uses of this chemical include rubber and plastic products.
2.2	Environmental Exposure and Fate
See environmental exposure and fate data at:
http://www.chem.unep.ch/irptc/sids/OECDSIDS/74851 .pdf.
3.	Human Health Hazard
See human health data at: http://www.chem.unep.ch/irptc/sids/OECDSIDS/74851 .pdf.

U.S. Environmental Protection Agency
Hazard Characterization Document
December, 2009
4. Hazard to the Environment
See environmental hazard data at: http://www.chem.unep.ch/irptc/sids/OECDSIDS/74851 .pdf.
The acute aquatic toxicity values for CASRN 74-85-1 from the SIDS documents are supported
by the ECOSAR (v 1.00a) predicted values as follows:
Acute Toxicity to Fish
96-h LC50 = 50-119.5 mg/L (QSAR estimate)
96-h LC50 = 96 mg/L (ECOSAR)
Acute Toxicity to Aquatic Invertebrates
48-h EC50 = 53-153 mg/L (QSAR estimate)
48-h EC50 = 48.4 mg/L (ECOSAR)
Toxicity to Aquatic Plants
72-h EC50 = 40 mg/L (biomass) (measured)
72-h EC50 = 72 mg/L (growth rate) (measured)
96-h EC50 = 16.7 mg/L (ECOSAR)