TSCA Section 5(a)(3)(C) Determination for Microbial Commercial Activity Notices
(MCANs) J-22-0001-0006

Number: J-22-0001-0006

TSCA Section 5(a)(3) Determination: The microorganisms are not likely to present an
unreasonable risk (5(a)(3)(C))

Chemical Name:

Generic: Chromosomally-modified Saccharomyces cerevisiae
Conditions of Use (intended, known, or reasonably foreseen)1:

Intended use(s) (generic): Manufacture and process for use and use in chemical production,

consistent with the manufacturing, processing, use, distribution, and disposal information
described in the MCANs.

Known conditions of use: Applying such factors as described in footnote 1, EPA evaluated

whether there are known conditions of use and found none.

Reasonably foreseen conditions of use(s): Applying such factors as described in footnote 1, EPA
evaluated whether there are reasonably foreseen conditions of use and found none.

Summary: The microorganisms are not likely to present an unreasonable risk based on low
human health hazard and low environmental hazard associated with the recipient
microorganisms and introduced genetic material. The recipient microorganisms are not
pathogenic to humans or animals and have an extensive history of safe use. The introduced
genetic modifications pose low concern for health and environmental hazard and do not include
antibiotic resistance markers.

Human Health Hazard2: Human health hazard is relevant to whether a new microorganism is
likely to present an unreasonable risk because the significance of the risk is dependent upon both

1	Under TSCA § 3(4), the term "conditions of use" means "the circumstances, as determined by the Administrator,
under which a chemical substance (including an intergeneric microorganism) is intended, known, or
reasonablyforeseen to be manufactured, processed, distributed in commerce, used, or disposed of." In general, EPA
considers the intended conditions of use of a new microorganism to be those identified in the section 5(a)
notification. Known conditions of use include activities within the United States that result from manufacture that is
exempt from MCAN submission requirements. Reasonably foreseen conditions of use are future circumstances,
distinct from known or intended conditions of use, under which the MCAN microorganisms may be manufactured,
processed, distributed, used, or disposed of. EPA expects that the identification of "reasonably foreseen" conditions
of use will be made on a fact-specific, case-by-case basis. EPA will apply its professional judgment and experience
when considering factors such as evidence of current use of the MCAN microorganisms outside the United States,
information about known or intended uses of microorganisms that are structurally analogous to the MCAN
microorganisms, and conditions of use identified in an initial MCAN submission that the submitter omits in a
revised MCAN. The sources EPA uses to identify reasonably foreseen conditions of use include searches of internal
confidential EPA MCAN databases (containing use information on analogue chemicals), other U.S. government
public sources, and Internet searches.

2	A microorganism is considered to have low human health hazard if it is not known to be a frank human pathogen
that causes disease in healthy adults, and/or animal studies have demonstrated a lack of pathogenicity or toxicity; a
microorganism is considered to have high human health hazard if there is evidence of adverse effects in humans or
conclusive evidence of severe effects in animal studies. In the absence of animal data on a microorganism, EPA may
use other data or information obtained through literature searches.

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TSCA Section 5(a)(3)(C) Determination for Microbial Commercial Activity Notices
(MCANs) J-22-0001-0006

the hazard (e.g., pathogenicity/toxicity) of the microorganism and the extent of exposure to the
microorganism. EPA estimated the human health hazard of these microorganisms based on data
for the recipient strains as well as the genetic modifications. There is low concern for human
health hazard for the microorganisms based on the recipient strains not being human pathogens
and the introduced genetic material encoding proteins that are not expected to increase the
potential for adverse human health effects.

Environmental Hazard3: Environmental hazard is relevant to whether a new microorganism is
likely to present unreasonable risks because the significance of the risk is dependent upon both
the hazard (e.g., pathogenicity/toxicity) of the microorganism and the extent of exposure to the
microorganism. EPA estimated the environmental hazard of these microorganisms based on data
for the recipient strains as well as information on the genetic modifications. There is low
concern for environmental hazard for these microorganisms based on the recipient strains not
being animal or plant pathogens and the introduced genetic material encoding proteins that are
not expected to increase the potential for adverse effects on animals or plants.

Exposure and Risk Characterization: The exposure to a new microorganism is potentially
relevant to whether a new microorganism is likely to present unreasonable risks because the
significance of the risk is dependent upon both the hazard (e.g., pathogenicity/toxicity) of the
microorganism and the nature and extent of exposure to the substance.

EPA considers workers to be a potentially exposed or susceptible subpopulation (PESS) on the
basis of greater exposure potential compared to the general population. EPA also considers PESS
in conducting general population drinking water exposures by evaluating risks associated with
water intake rates for multiple age groups, ranging from infants to adults. EPA considers
consumers of specific products to be a potentially exposed or susceptible subpopulation on the
basis of greater exposure potential compared to the general population who do not use specific
products.

EPA did not estimate the occupational or environmental exposures because EPA determined that
the microorganisms present both low human health hazard and low environmental hazard. No
consumer use was identified, so risks to consumers were not assessed.

Due to low hazard, EPA believes that these microorganisms would not be likely to present an
unreasonable risk even if exposures were high. Therefore, EPA concludes that the new
microorganisms are not likely to present unreasonable risk under the conditions of use.

1/20/2022		/s/

Date:	Madison H. Le, Director

New Chemicals Division
Office of Pollution Prevention and Toxics
U.S. Environmental Protection Agency

3 A microorganism is considered to be of low ecological hazard if it is not known to be an animal or plant pathogen,
and the genetic modifications do not impart pathogenic or toxigenic traits, and the introduced genetic material does
not provide a selective growth advantage in outcompeting indigenous microbial communities in the environment.

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