U.S. Environmental Protection Agency
Hazard Characterization Document
December, 2009
SCREENING-LEVEL HAZARD CHARACTERIZATION
2, 4-Pentanedione (CASRN 123-54-6)
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
environment.
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.

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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.
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U.S. Environmental Protection Agency
Hazard Characterization Document
December, 2009
Chemical Abstract Service
Registry Number
(CASRN)
123-54-6
Chemical Abstract Index
Name
Acetylacetone; acetyl-propanone-2; 2,4-dioxopentane
Structural Formula
Summary
CASRN 123-54-6 is a colorless to slightly yellowish liquid with high water solubility and high
vapor pressure. It is expected to have high mobility in soil. CASRN 123-54-6 achieved 79-88%
of its theoretical biochemical oxygen demand (BOD) over a 28 day incubation period and is
considered readily biodegradable. The rate of volatilization is considered moderate. The rate of
hydrolysis is considered negligible. The rate of atmospheric photooxidation is negligible. An
estimated bioaccumulation factor of 1.0 suggests bioconcentration is low. CASRN 123-54-6 is
expected to have low persistence (PI) and low bioaccumulation potential (Bl).
The acute toxicity of CASRN 123-54-6 to rats is low via the oral route and moderate via the
dermal and inhalation routes. CASRN 123-54-6 is mildly irritating to the rabbit eye. In a 14-
week repeated-dose inhalation toxicity study in rats, mortality in 30/30 females and 10/30 males
at 2711 mg/L was observed. At 1217 mg/L, slight decreases in body weight gain (5% lower than
controls) were observed in females, and minor alterations in hematology and in serum and urine
analyses were observed in both sexes. The NOAEC for systemic toxicity is 417 mg/L. There
are no specific reproductive toxicity studies for this chemical. However, no treatment-related
histological or organ weight changes were observed in reproductive organs examined from the
14-week repeated-dose inhalation study in rats. The NOAEC for reproductive toxicity in rats is
2711 mg/L. A prenatal developmental toxicity study in rats exposed via vapor inhalation to
CASRN 123-54-6 observed a significant reduction in maternal body weight gain at 1668 mg/L,
the highest dose tested. The NOAEC for maternal toxicity is 834 mg/L. Signs of developmental
toxicity consist of reduced fetal weights and reduced fetal ossification at 834 mg/L. The
NOAEC for developmental toxicity is 209 mg/L. Equivocal results are observed on reproductive
and gestational parameters in a dominant lethal assay. CASRN 123-54-6 is not mutagenic in
bacterial cells, but induced chromosomal aberrations in mammalian cells in vitro. CASRN 123-
54-6 does not induce micronuclei in vivo.
The 96-hour LC50 of CASRN 123-54-6 to fish is 60.1 mg/L. For a 48-hour static test in closed
system for aquatic invertebrates of this chemical, the EC50 is 34.4 mg/L. The 24-hour EC50 value
for aquatic plants exposed to this chemical is >300mg/L, this value is supported by the ECOSAR
96-hour EC50 algal value of 10.8 mg/L.	
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U.S. Environmental Protection Agency
Hazard Characterization Document
December, 2009
No data gaps were identified for SIDS endpoints.
The sponsor country, Germany, presented the SIDS documents at the OECD SIAM 13 during
November 2001. The SIAR, SIAP and Dossier was finalized by OECD and published by UNEP
in April 2004 fhttp ://www.chem.unep. ch/irptc/sids/OECD SIDS/PENT ANEDIONE.pdf). This
hazard characterization includes EPA review of the SIDS documents and any 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/PENTANEDIONE.pdf.
1.2	Physical-Chemical Properties
See physical-chemical properties at:
http://www.chem.unep.ch/irptc/sids/OECDSIDS/PENTANEDIONE.pdf.
2. General Information on Exposure
2.1	Production Volume and Use Pattern
CASRN 123-54-6 had an aggregated production and/or import volume in the United States
between 1 and 10 million pounds during calendar year 2005.
Non-confidential information in the IUR indicated that the industrial processing and uses of the
chemical include intermediates, solvents (which become part of product formulation or mixture),
and solvents (for chemical manufacture and processing and are not part of product at greater than
1% by weight). Non-confidential commercial and consumer uses of this chemical include paints
and coating, and other.
2.2	Environmental Exposure and Fate
See environmental exposure and fate data at:
http://www.chem.unep.ch/irptc/sids/OECDSIDS/PENTANEDIONE.pdf.
3. Human Health Hazard
See human health hazard data at:
http://www.chem.unep.ch/irptc/sids/OECDSIDS/PENTANEDIONE.pdf.
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U.S. Environmental Protection Agency
Hazard Characterization Document
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4. Hazard to the Environment
See environmental hazard data at:
http://www.chem.unep.ch/irptc/sids/OECDSIDS/PENTANEDIONE.pdf.
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