[Federal Register Volume 81, Number 106 (Thursday, June 2, 2016)]
[Proposed Rules]
[Pages 35275-35290]
[FR Doc No: 2016-12464]

=======================================================================
-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 372

[EPA-HQ-TRI-2015-0607; FRL-9943-55]
RIN 2025-AA42

Addition of Hexabromocyclododecane (HBCD) Category; Community
Right-to-Know Toxic Chemical Release Reporting

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: EPA is proposing to add a hexabromocyclododecane (HBCD)
category to the list of toxic chemicals subject to reporting under
section 313 of the Emergency Planning and Community Right-to-Know Act
(EPCRA) and section 6607 of the Pollution Prevention Act (PPA). EPA is
proposing to add this chemical category to the EPCRA section 313 list
because EPA believes HBCD meets the EPCRA section 313(d)(2)(B) and (C)
toxicity criteria. Specifically, EPA believes that HBCD can reasonably
be anticipated to cause developmental and reproductive effects in
humans and is highly toxic to aquatic and terrestrial organisms. In
addition, based on the available bioaccumulation and persistence data,
EPA believes that HBCD should be classified as a persistent,
bioaccumulative, and toxic (PBT) chemical and assigned a 100-pound
reporting threshold. Based on a review of the available production and
use information, members of the HBCD category are expected to be
manufactured, processed, or otherwise used in quantities that would
exceed a 100-pound EPCRA section 313 reporting threshold.

DATES: Comments must be received on or before August 1, 2016.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
TRI-2015-0607, by one of the following methods:
     Federal eRulemaking Portal: http://www.regulations.gov.
Follow the online instructions for submitting comments. Do not submit
electronically any information you consider to be Confidential Business
Information (CBI) or other information whose disclosure is restricted
by statute.
     Mail: Document Control Office (7407M), Office of Pollution
Prevention and Toxics (OPPT), Environmental Protection Agency, 1200
Pennsylvania Ave. NW., Washington, DC 20460-0001.
     Hand Delivery: To make special arrangements for hand
delivery or delivery of boxed information, please follow the
instructions at http://www.epa.gov/dockets/where-send-comments-epa-dockets#hq.

Additional instructions on commenting or visiting the docket, along
with more information about dockets generally, is available at http://www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT:
    For technical information contact: Daniel R. Bushman, Toxics
Release Inventory Program Division (7409M), Office of Pollution
Prevention and Toxics, Environmental Protection Agency, 1200
Pennsylvania Ave. NW., Washington, DC 20460-0001; telephone number:
(202) 566-0743; email<EMAIL_ADDRESS>    For general information contact: The Emergency Planning and
Community Right-to-Know Hotline; telephone numbers: toll free at (800)
424-9346 (select menu option 3) or<PHONE_NUMBER> in Virginia and
Alaska; or toll free, TDD<PHONE_NUMBER>; or go to http://www.epa.gov/superfund/contacts/infocenter/.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this notice apply to me?

    You may be potentially affected by this action if you manufacture,
process, or otherwise use HBCD. The following list of North American
Industrial Classification System (NAICS) codes is not intended to be
exhaustive, but rather provides a guide to help readers determine
whether this document applies to them. Potentially affected entities
may include:
     Facilities included in the following NAICS manufacturing
codes (corresponding to Standard Industrial Classification (SIC) codes
20 through 39): 311*, 312*, 313*, 314*, 315*, 316, 321, 322, 323*, 324,
325*, 326*, 327, 331, 332, 333, 334*, 335*, 336, 337*, 339*, 111998*,
211112*, 212324*, 212325*, 212393*, 212399*, 488390*, 511110, 511120,
511130, 511140*, 511191, 511199, 512220, 512230*, 519130*, 541712*, or
811490*.

* Exceptions and/or limitations exist for these NAICS codes.
     Facilities included in the following NAICS codes
(corresponding to SIC codes other than SIC codes 20 through 39):
212111, 212112, 212113 (corresponds to SIC code 12, Coal Mining (except
1241)); or 212221, 212222, 212231, 212234, 212299 (corresponds to SIC
code 10, Metal Mining (except 1011, 1081, and 1094)); or 221111,
221112, 221113, 221118, 221121, 221122, 221330 (Limited to facilities
that combust coal and/or oil for the purpose of generating power for
distribution in commerce) (corresponds to SIC codes 4911, 4931, and
4939, Electric Utilities); or 424690, 425110, 425120 (Limited to
facilities previously classified in SIC code 5169, Chemicals and Allied
Products, Not Elsewhere Classified); or 424710 (corresponds to SIC code
5171, Petroleum Bulk Terminals and Plants); or 562112 (Limited to
facilities primarily engaged in solvent recovery services on a contract
or fee basis (previously classified under SIC code 7389, Business
Services, NEC)); or 562211, 562212, 562213, 562219, 562920 (Limited to
facilities regulated under the Resource Conservation and Recovery Act,
subtitle C, 42 U.S.C. 6921 et seq.) (corresponds to SIC code 4953,
Refuse Systems).
     Federal facilities.
    To determine whether your facility would be affected by this
action, you should carefully examine the applicability criteria in part
372, subpart B of Title 40 of the Code of Federal Regulations. If you
have questions regarding the applicability of this action to a
particular entity, consult the person listed under FOR FURTHER
INFORMATION CONTACT.

B. What action is the Agency taking?

    EPA is proposing to add a hexabromocyclododecane (HBCD) category to
the list of toxic chemicals subject to reporting under EPCRA section
313 and PPA section 6607. As discussed in more detail later in this
document, EPA is proposing to add this chemical category to the EPCRA
section 313 list because EPA believes HBCD meets the EPCRA section
313(d)(2)(B) and (C) toxicity criteria.

C. What is the Agency's authority for taking this action?

    This action is issued under EPCRA sections 313(d) and 328, 42
U.S.C. 11023 et seq., and PPA section 6607, 42 U.S.C. 13106. EPCRA is
also referred to as Title III of the Superfund Amendments and
Reauthorization Act of 1986.
    Section 313 of EPCRA, 42 U.S.C. 11023, requires certain facilities
that manufacture, process, or otherwise use listed toxic chemicals in
amounts above reporting threshold levels to report their environmental
releases and other waste management quantities of such chemicals
annually. These facilities must also report pollution prevention and
recycling data for such chemicals, pursuant to section 6607 of the PPA,
42 U.S.C. 13106. Congress established an initial list of toxic
chemicals that comprised 308 individually listed chemicals and 20
chemical categories.
    EPCRA section 313(d) authorizes EPA to add or delete chemicals from
the list and sets criteria for these actions. EPCRA section 313(d)(2)
states that EPA may add a chemical to the list if any of the listing
criteria in EPCRA section 313(d)(2) are met. Therefore, to add a
chemical, EPA must demonstrate that at least one criterion is met, but
need not determine whether any other criterion is met. Conversely, to
remove a chemical from the list, EPCRA section 313(d)(3) dictates that
EPA must demonstrate that none of the following listing criteria in
EPCRA section 313(d)(2)(A)-(C) are met:
     The chemical is known to cause or can reasonably be
anticipated to cause significant adverse acute human health effects at
concentration levels that are reasonably likely to exist beyond
facility site boundaries as a result of continuous, or frequently
recurring, releases.
     The chemical is known to cause or can reasonably be
anticipated to cause in humans: Cancer or teratogenic effects, or
serious or irreversible reproductive dysfunctions, neurological
disorders, heritable genetic mutations, or other chronic health
effects.
     The chemical is known to cause or can be reasonably
anticipated to cause, because of its toxicity, its toxicity and
persistence in the environment, or its toxicity and tendency to
bioaccumulate in the environment, a significant adverse effect on the
environment of sufficient seriousness, in the judgment of the
Administrator, to warrant reporting under this section.
    EPA often refers to the EPCRA section 313(d)(2)(A) criterion as the
``acute human health effects criterion;'' the EPCRA section
313(d)(2)(B) criterion as the ``chronic human health effects
criterion;'' and the EPCRA section 313(d)(2)(C) criterion as the
``environmental effects criterion.''
    EPA published in the Federal Register of November 30, 1994 (59 FR
61432) (FRL-4922-2), a statement clarifying its interpretation of the
EPCRA section 313(d)(2) and (d)(3) criteria for modifying the EPCRA
section 313 list of toxic chemicals.

II. Background Information

A. What is HBCD?

    HBCD is a cyclic aliphatic hydrocarbon consisting of a 12-membered
carbon ring with 6 bromine atoms attached (molecular formula
C12H18Br6). HBCD has 16 possible
stereoisomers. Technical grades of HBCD consist predominantly of three
diastereomers, [alpha]-, [szlig]- and [gamma]-HBCD (Ref. 1). HBCD may
be designated as a non-specific mixture of all isomers
(hexabromocyclododecane, Chemical Abstracts Service Registry Number
(CASRN) 25637-99-4) or as a mixture of the three main diastereomers
(1,2,5,6,9,10-hexabromocyclododecane, CASRN 3194-55-6) (Ref 1). The
main use of HBCD is as a flame retardant in expanded polystyrene foam
(EPS) and

extruded polystyrene foam (XPS) (Ref. 2). EPS and XPS are used
primarily for thermal insulation boards in the building and
construction industry. HBCD may also be used as a flame retardant in
textiles including: upholstered furniture, upholstery seating in
transportation vehicles, draperies, wall coverings, mattress ticking,
and interior textiles, such as roller blinds (Ref. 2). In addition,
HBCD is used as a flame retardant in high-impact polystyrene for
electrical and electronic appliances such as audio-visual equipment, as
well as for some wire and cable applications (Ref. 2).
    Concerns for releases and uses of HBCD have been raised because it
is found world-wide in the environment and wildlife and has also been
found in human breast milk, adipose tissue and blood (Ref. 1). HBCD is
known to bioaccumulate and biomagnify in the food chain and has been
detected over large areas and in remote locations in environmental
monitoring studies (Ref. 1).

B. How is EPA proposing to list HBCD under EPCRA section 313?

    HBCD is identified through two primary CASRNs 3194-55-6
(1,2,5,6,9,10-hexabromocyclododecane) and 25637-99-4
(hexabromocyclododecane) (Ref. 1). EPA is proposing to create an HBCD
category that would cover these two chemical names and CASRNs. The HBCD
category would be defined as: Hexabromocyclododecane and would only
include those chemicals covered by the following CAS numbers:
     3194-55-6; 1,2,5,6,9,10-Hexabromocyclododecane.
     25637-99-4; Hexabromocyclododecane.

As a category, facilities that manufacture, process or otherwise use
HBCD covered under both of these names and CASRNs would file just one
report.
    In addition to listing HBCD as a category, EPA is proposing to add
the HBCD category to the list of chemicals of special concern. There
are several chemicals and chemical categories on the EPCRA section 313
chemical list that have been classified as chemicals of special concern
because they are PBT chemicals (see 40 CFR 372.28(a)(2)). In a final
rule published in the Federal Register of October 29, 1999 (64 FR
58666) (FRL-6389-11), EPA established the PBT classification criteria
for chemicals on the EPCRA section 313 chemical list. For purposes of
EPCRA section 313 reporting, EPA established persistence half-life
criteria for PBT chemicals of 2 months in water/sediment and soil and 2
days in air, and established bioaccumulation criteria for PBT chemicals
as a bioconcentration factor (BCF) or bioaccumulation factor (BAF) of
1,000 or higher. Chemicals meeting the PBT criteria were assigned 100-
pound reporting thresholds. With regards to setting the EPCRA section
313 reporting thresholds, EPA set lower reporting thresholds (10
pounds) for those PBT chemicals with persistence half-lives of 6 months
or more in water/sediment or soil and with BCF or BAF values of 5,000
or higher, these chemicals were considered highly PBT chemicals. The
data presented in this proposed rule support classifying the HBCD
category as a PBT chemical category with a 100-pound reporting
threshold.

III. What is EPA's evaluation of the toxicity, bioaccumulation, and
environmental persistence of HBCD?

    EPA evaluated the available literature on the human health
toxicity, ecological toxicity, bioaccumulation potential, and
environmental persistence of HBCD (Ref. 1). Unit III.A. provides a
review of the human health toxicity studies and EPA's conclusions
regarding the human health hazard potential of HBCD. Unit III.B.
discusses the ecological toxicity of HBCD, Unit III.C. contains
information on the bioaccumulation potential of HBCD, and Unit III.D.
provides information on the environmental persistence of HBCD.

A. What is EPA's review of the human health toxicity data for HBCD?

    1. Toxicokinetics. HBCD is absorbed via the gastrointestinal tract
and metabolized in rodents (Refs. 3, 4, 5, and 6). Once absorbed, HBCD
is distributed to a number of tissues, including fatty tissue, muscle,
and the liver (Refs. 7, 8, 9, 10, 11, and 12). Elimination of HBCD is
predominantly via feces (as the parent compound), but it is also
eliminated in urine (as secondary metabolites) (Refs. 3, 4, and 5).
HBCD has been detected in human milk, adipose tissue, and blood (Refs.
13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, and 24). The composition of
HBCD isomers in most rodent toxicity studies resembles that of
industrial grade HBCD, which may differ from human exposure to certain
foods that have been shown to contain elevated fractions of [alpha]-
HBCD (Ref. 25).
    2. Effects of acute exposure. HBCD was not found to be highly toxic
in acute oral, inhalation, and dermal studies in rodents. One study
reported an oral median lethal dose (LD50) of >10,000
milligrams per kilogram (mg/kg) in Charles River rats (Ref. 26).
Another study by the same researchers, however, reported an
LD50 of 680 mg/kg for females and 1,258 mg/kg for males in
Charles River CD rats (Ref. 27). Two other studies reported an oral
LD50 of >5,000 mg/kg in Sprague-Dawley rats and >10,000 mg/
kg in NR rats (Refs. 28 and 29). An oral study in NR mice reported an
LD50 of >6,400 mg/kg (Ref. 30). Acute inhalation studies in
rats have generally concluded that HCBD is not highly toxic, with a
median lethal concentration (LC50) reported by Gulf South
Research Institute of >200 milligrams per liter (mg/L) (Refs. 26, 27,
29, 31). Acute dermal toxicity studies have generally shown HBCD not to
be highly toxic in rabbits (Refs. 27, 29, 31, and 32). One dermal study
reported an LD50 of 3,969 mg/kg (Ref. 27). Additionally,
HBCD is not a dermal irritant in rabbits (Refs. 27, 29, and 31), but it
is a mild skin allergen in guinea pigs (Ref. 32). Acute eye irritation
studies have concluded that HBCD is a primary eye irritant (Ref. 27)
and a mild, transient ocular irritant (Ref. 29).
    3. Effects of short-term and subchronic exposure. In subacute and
subchronic studies, HBCD demonstrated effects on the thyroid and liver
(Refs. 8, 33, 34, and 35). In a subacute study, van der Ven et al.
(Ref. 8) exposed Wistar rats (5/sex/dose) by gavage to a mixture of
HBCD dissolved in corn oil at concentrations resulting in doses of 0.3,
1.0, 3.0, 10, 30, 100, and 200 milligrams per kilogram per day (mg/kg/
day) for 28 days. The isomeric composition of the HBCD was 10.3%
[alpha], 8.7% [beta], and 81.0% [gamma]. The authors reported a
benchmark dose lower bound confidence limit (BMDL) of 29.9 mg/kg/day
for an increase in pituitary weight, a BMDL of 1.6 mg/kg/day for an
increase in thyroid weight, and a BMDL of 22.9 mg/kg/day for an
increase in liver weight. The increase in thyroid weight was the most
sensitive end point observed and, according to research by EPA, is
considered relevant to humans (Ref. 36). Additionally, histopathology
of the thyroid demonstrated that thyroid follicles were smaller,
depleted, and had hypertrophied epithelium in female rats.
    In another subacute study, HBCD was administered orally by gavage
in corn oil to Sprague-Dawley Crl:CD BR rats for 28 days at doses of 0,
125, 350, or 1,000 mg/kg/day (6 rats/sex/dose in 125 and 350 mg/kg/day
groups and 12 rats/sex/dose in the control and 1,000 mg/kg/day groups)
(Ref. 33). At the end of 28 days, 6 rats/sex/dose were necropsied,
while the remaining rats in the control and 1,000 mg/kg/day groups were
untreated for a 14-day recovery period prior to necropsy. The authors
reported

increased absolute and liver to body weight ratios in females, but the
authors considered the findings to be adaptive and not adverse. This
study also identified a no-observed-adverse-effect level (NOAEL) of
1,000 mg/kg/day.
    In an older subacute study (Ref. 37), an HBCD product was
administered to Sprague-Dawley rat (10/sex/group) at doses of 0, 1,
2.5, and 5% of the diet for 28 days. Doses were calculated to be 0,
940, 2,410, 4,820 mg/kg/day. Mean liver weight (both absolute and
relative) was increased in all dose groups, but no microscopic
pathology was detected. Thyroid hyperplasia was observed in some
animals at all doses in addition to slight numerical development of the
follicles and ripening follicles in the ovaries at the high dose. The
authors concluded that these observed effects were not pathologic and
reported a NOAEL of 940 mg/kg/day (Ref. 37).
    In a subchronic study, Chengelis (Refs. 34 and 35) administered
HBCD by oral gavage in corn oil daily to Crl:CD(SD)IGS BR rats (15/sex/
dose) at dose levels of 0, 100, 300, or 1,000 mg/kg/day for 90 days. At
the end of 90 days, 10 rats/sex/dose were necropsied, while the
remaining rats were untreated for a 28-day recovery period prior to
necropsy. The authors reported significant treatment-related changes in
rats, including decreased liver weight and histopathological changes,
but the authors considered these changes mild, reversible, and
adaptive. Decreased liver weight accompanied by the observed
histopathological changes, however, can be considered an adverse
effect. Therefore, EPA identified a lowest-observed-adverse-effect
level (LOAEL) of 100 mg/kg/day based on these changes.
    In an older subchronic study (Ref. 38) an HBCD product was
administered to Sprague-Dawley rats (10/sex/group) at doses of 0, 0.16,
0.32, 0.64, and 1.28% of the diet for 90 days. Doses were calculated to
be 0, 120, 240, 470, and 950 mg/kg/day. An increase in relative liver
weight was observed and was accompanied by fatty accumulation. The
pathology report concluded that although fat was visible
microscopically in treated rats, the change was not accompanied by any
pathology, and therefore could not be defined as ``fatty liver.'' No
histological changes were found in any other organ. The authors
concluded that the increased liver weight and the fat deposits, both of
which were largely reversible when administration of HBCD was stopped,
were the result of a temporary increase in the activity of the liver.
They identified a NOAEL of 950 mg/kg/day.
    4. Carcinogenicity. No adequate studies were found evaluating the
carcinogenicity of HBCD in animals or humans. One non-guideline study
(Ref. 39) was cited in the U.S. EPA's Flame Retardant Alternatives for
Hexabromocyclododecane (HBCD): Final Report (Ref. 40), but this study
was not adequate to draw conclusions regarding carcinogenicity.
    5. Developmental and reproductive toxicity. The developmental and
reproductive toxicity of HBCD have been investigated in several
studies. In a 1-generation study that included additional
immunological, endocrine and neurodevelopmental endpoints, van der Ven
et al. (Ref. 9) exposed Wistar rats (10/sex/dose) to a composite
mixture of technical-grade HBCD (10.3% [alpha], 8.7% [beta], and 81.0%
[gamma]) in the diet at concentrations resulting in doses of 0.1, 0.3,
1.0, 3.0, 10, 30, or 100 mg/kg/day. In the highest dose group (100 mg/
kg/day) body weight decreases of 7-36% in males and 10-20% in females
were observed in first generation (F1) pups. The authors observed
decreases in kidney and thymus weight in both F1 males and females.
Decreases in testes, adrenal, prostate, heart, and brain weights in F1
males were also observed. No histopathological changes, however, were
observed in any of these organs. Other developmental effects were
observed, including: Immune system effects, indications of liver
toxicity, and decreases in bone mineral density at very low doses
(i.e., <1.3 mg/kg/day). The authors noted that the vehicle used (corn
oil) may have affected some observations at higher doses, including:
Increased mortality during lactation, decreased liver weight in males,
decreased adrenal weight in females, decreased plasma cholesterol in
females, and other immunological markers of toxicity. Increased
anogenital distance was observed in males at 100 mg/kg on postnatal day
(PND) 4, but not on PND 7 or 21. There was no effect on preputial
separation. The time to vaginal opening was delayed in females at the
100 mg/kg dose. There were no effects of HBCD exposure on thyroid
hormones triiodothyronine (T3) and thyroxine (T4) in either the
parental or F1 animals. There were no effects on thyroid weight or
thyroid pathology in the F1 animals (parents were not examined). The
most sensitive endpoints with valid benchmark dose (BMD)/BMDL ratios
for female rats were decreased bone mineral density with a BMDL of
0.056 mg/kg/day (BMD of 0.18 mg/kg/day) at a benchmark response (BMR)
of 10% and decreased concentrations of apolar retinoids in the liver
with a BMDL of 1.3 mg/kg/day (BMD = 5.1 mg/kg/day) at a BMR of 10%. The
most sensitive endpoint with a valid BMD/BMDL ratio for male rats was
an increased IgG response to sheep red blood cells with a BMDL of 0.46
mg/kg/day (BMD = 1.45 mg/kg/day) at a BMR of 20%. There were no
significant effects of HBCD exposure on any measure of reproduction,
including: Mating success, time to gestation, duration of gestation,
number of implantation sites, pup mortality (at birth and throughout
lactation), or sex ratios within a litter. Therefore, a BMDL for
reproductive toxicity could not be derived for this study.
    Saegusa et al. (Ref. 41) exposed pregnant Sprague-Dawley rats (10/
sex/dose) to HBCD from gestation day 10 until PND 20 at dietary
concentrations of 0, 100, 1,000, or 10,000 parts per million (ppm) in a
soy-free diet. The authors observed increased relative thyroid weight
and decreased T3 levels in F1 male Sprague-Dawley rats at postnatal
week (PNW) 11 following dietary exposure to 1,000 ppm (approximately
146.3 mg/kg/day) HBCD. The authors also reported a significant
reduction in the number of CNPase-positive oligodendrocytes at 10,000
ppm (approximately 1,504.8 mg/kg/day). EPA identified a maternal LOAEL
of 10,000 ppm (about 1,504.8 mg/kg/day) based on increased incidence of
thyroid follicular cell hypertrophy, and a developmental LOAEL of 1,000
ppm (about 146.3 mg/kg/day) based on increased relative thyroid weight
and decreased T3 levels in F1 males at PNW 11. Changes in reproductive
endpoints (e.g., the number of implantation sites, live offspring, sex
ratio) were not observed. Therefore, a LOAEL for reproductive toxicity
could not be determined for this study.
    Ema et al. (Ref. 42) administered HBCD to groups of male and female
Crl:CD(SD) rats (24/sex/dose, as a mixture of [alpha]-HBCD, [beta] -
HBCD, and [gamma]-HBCD with proportions of 8.5, 7.9, and 83.7%,
respectively) in the diet at concentrations of 0, 150, 1,500, or 15,000
ppm from 10 weeks prior to mating through mating, gestation, and
lactation. The authors reported a decrease in the number of primordial
follicles in F1 female rats at 1,500 ppm (approximately 138 mg/kg/day)
and a significant increase in the number of litters lost in the F1
generation at 15,000 ppm (approximately 1,363 mg/kg/day). These authors
reported no other significant treatment-related effects in any
generation for indicators of reproductive health, including: Estrous
cyclicity, sperm count and morphology, copulation index, fertility
index,

gestation index, delivery index, gestation length, number of pups
delivered, number of litters, or sex ratios. The authors reported a
reduced viability index on day 4 and day 21 of lactation among second
generation (F2) offspring at 15,000 ppm (approximately 1,363 mg/kg/
day). They observed additional developmental effects at doses as low as
1,500 ppm (approximately 115 and 138 mg/kg/day for F1 males and
females, respectively), including: An increase in dihydrotestosterone
(DHT) in F1 males and an increased incidence of animals with decreased
thyroid follicle size in both sexes and generations. These authors
reported no effects on sexual development indicated by anogenital
distance, vaginal opening, or preputial separation among F1 or F2
generations. The percentage of pups with completed eye opening on PND
14 was significantly decreased compared to controls in F2 females at
1,500 ppm and in F2 males and females at 15,000 ppm. Fewer F2 females
exposed to 15,000 ppm HBCD completed the mid-air righting reflex
(76.9%) than control F2 females (100%). These findings were not
consistent over generations or sexes and were not considered treatment
related. No other effects of HBCD exposure on the development of
reflexes were observed in either F1 or F2 progeny. EPA identified a
maternal LOAEL of 150 ppm (about 14 mg/kg/day) based on increased
thyroid-stimulating hormone (TSH). A reproductive LOAEL of 1,500 ppm
(about 138 mg/kg/day) was identified based on a decreased number of
primordial follicles in the ovary observed in F1 females. A
developmental LOAEL of 15,000 ppm (about 1,142 mg/kg/day for males and
1,363 mg/kg/day for females) was identified based on increased pup
mortality during lactation in the F2 generation.
    Murai et al. (Ref. 43) fed female Wistar rats HBCD in the diet at
concentrations of 0, 0.01, 0.1, or 1% throughout gestation (Days 0-20).
Dams in the high-dose group demonstrated a statistically significant
decrease (8.4%) in food consumption and increase in liver weight (13%)
in comparison with controls. There were no treatment-related effects on
maternal or fetal body weight. There were no effects on the number of
implants; number of resorbed, dead, or live fetuses; body weight of
live fetuses; or incidence of external or visceral abnormalities. A few
skeletal variations were present but were also observed in controls and
not considered significant. There were no effects on weaning or
survival. The European Commission (Ref. 44) used the study's data to
calculate the doses to be 0, 7.5, 75, and 750 mg/kg/day (based on the
assumption of a mean animal weight of 200 grams (g) and food
consumption of 15 g/day). They concluded that the offspring NOAEL was
750 mg/kg/day and the maternal LOAEL was 750 mg/kg/day based on a 13%
liver weight increase in the high dose group.
    Eriksson et al. (Ref. 45) conducted a study that examined behavior,
learning, and memory in adult mice following exposure to HBCD on PND
10. The authors administered a single oral dose of HBCD (mixture of,
[alpha]-, [beta]-, and [gamma]-diastereoisomers) dissolved in a fat
emulsion at 0, 0.9, or 13.5 mg/kg/day on PND 10 to male and female NMRI
mice. The authors concluded that exposure on PND 10 affected
spontaneous motor behavior, learning, and memory in adult mice in a
dose-dependent manner. The authors identified the lowest exposure
level, 0.9 mg/kg, as the LOAEL based on significantly reduced mean
locomotor activity compared with controls during the first 20-minute
interval of testing. EPA, however, identified a LOAEL of 13.5 mg/kg/day
based on decreased habituation, locomotion, and rearing during all
intervals. This study was not conducted according to current guidelines
(Ref. 46) and Good Laboratory Practices; therefore, EPA reserves
judgment on the significance of these findings.
    6. Genotoxicity. A limited number of studies investigated the
genotoxicity of HBCD. These studies indicate that HBCD is not likely to
be genotoxic (Refs. 47, 48, 49, 50, 51, 52, 53, and 54).
    7. Conclusions regarding the human hazard potential of HBCD. The
available evidence indicates that HBCD has the potential to cause
developmental and reproductive toxicity at moderately low to low doses.
While there were some indications of liver toxicity in some short-term
and subchronic studies, the evidence for these effects is not
sufficient to support listing. The available evidence for developmental
and reproductive toxicity, however, is sufficient to conclude that HBCD
can be reasonably anticipated to cause moderately high to high chronic
toxicity in humans based on the EPCRA section 313 listing criteria
published in the Federal Register of November 30, 1994 (59 FR 61432)
(FRL-4922-2).

B. What is EPA's review of the ecological toxicity of HBCD?

    HBCD can cause effects on survival, growth, reproduction,
development, and behavior in aquatic and terrestrial species. Observed
acute toxicity values as low as 0.009 mg/L for a 72-hour
EC50 (i.e., the concentration that is effective in producing
a sublethal response in 50% of test organisms) based on reduced growth
in the marine algae Skeletonema costatum (Ref. 55) indicate high acute
aquatic toxicity. Observed chronic aquatic toxicity values as low as
0.0042 mg/L (maximum acceptable toxicant concentration (MATC)) for
reduced size (length) of surviving young in water fleas (Daphnia magna)
(Ref. 56) indicate high chronic aquatic toxicity. Reduced chick
survival in Japanese quails (Coturnix coturnix japonica) fed a 15 parts
per million (ppm) HBCD diet (2.1 mg/kg/day) (Ref. 57 as cited in Ref.
58) and altered reproductive behavior (reduced courtship and brood-
rearing activity) and reduced egg size in American kestrels (Falco
sparverius) fed 0.51 mg/kg/day (Refs. 59, 60, 61, and 62) indicate high
toxicity to terrestrial species as well.
    Assessment of HBCD's aquatic toxicity is complicated by its low
water solubility and differences in the solubility of the three main
HBCD isomers, which makes testing difficult and interpretation
uncertain for studies conducted above the water solubility. Studies
conducted at concentrations above the water solubility of HBCD are
essentially testing the effects at the maximum HBCD concentration
possible. In some acute and chronic aquatic toxicity studies conducted
using methods, test species, and endpoints recommended by EPA, no
effects were reported at or near the limit of water solubility.
However, water solubility is not considered a limiting factor for
hazard determination for aquatic species since there are studies
showing adverse effects at or below the water solubility of HBCD. In
addition, the potential for HBCD to bioaccumulate, biomagnify, and
persist in the environment, significantly increases concerns for
effects on aquatic organisms.
    A wide range of effects of HBCD have been reported in fish (e.g.,
developmental toxicity, embryo malformations, reduced hatching success,
reduced growth, hepatic enzyme and biomarker effects, thyroid effects,
deoxyribonucleic acid (DNA) damage to erythrocytes, and oxidative
damage) and in invertebrates (e.g., degenerative changes, morphological
abnormalities, decreased hatching success, and altered enzyme activity)
(Refs. 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, and 74). Reduced
thyroid hormone (triiodothyronine, T3, and thyroxine, T4) levels in
rainbow trout (Oncorhynchus mykiss) (Refs. 68 and 69), are similar to
those observed in mammals. Reduced T4 levels were also

reported in birds exposed to HBCD (Ref. 61).
    1. Acute aquatic toxicity. Adverse effects observed following acute
exposure were found in studies with marine algae, including EPA-
recommended estuarine/marine algae species Skeletonema costatum (Ref.
75 as cited in Refs. 44 and 76, Refs. 55 and 77), a series of short-
term (72 to 120-hour) early life stage tests with zebrafish (Danio
rerio) embryos (Refs. 64, 65, 67, and 72), and short-term (72-hour)
results from an early life stage test with sea urchin embryos (Ref.
63). Effects in these studies, reported at concentrations as low as
0.009 mg/L (measured) in algae, 0.01 mg/L (nominal) in zebrafish
embryos, and 0.064 mg/L (nominal) in sea urchin embryos, indicate high
acute toxicity. Walsh et al. (Ref. 55) reported measured 72-hour
EC50 values in Skeletonema costatum ranging from 0.009 to
0.012 mg/L based on reduced growth rate in five different types of
saltwater media (0.010 mg/L in seawater itself). The study tested two
other marine algal species, Chlorella sp. and Thalassiosira pseudonana,
that were also found to be inhibited by HBCD, albeit at higher
concentrations than Skeletonema costatum. EC50 values for
reduced growth in these species were 0.05-0.37 mg/L (0.08 mg/L in
seawater) for Thalassiosira pseudonana and >1.5 mg/L for Chlorella sp.
    Subsequent studies by Desjardins et al. (Ref. 75) confirmed the
high acute toxicity of HBCD to Skeletonema costatum. In these studies,
single concentrations were tested, but the assays were conducted
without solvent and the concentrations were measured. Desjardins et al.
(Ref. 75) reported approximately 10% inhibition of growth in
Skeletonema costatum exposed to 0.041 mg/L for 72 hours. Desjardins et
al. (Ref. 77) found that a saturated solution of 0.0545 mg/L resulted
in 51% growth inhibition after 72 hours of exposure. The latter result
corresponds to an approximate EC50 of 0.052 mg/L.
    Zebrafish embryo studies reported a variety of effects on embryos
and larvae at low HBCD concentrations. In the Deng et al. (Ref. 64)
study, developmental toxicity endpoints were assessed at 96 hours post-
fertilization in embryos/larvae exposed to HBCD starting 4 hours post-
fertilization. Survival of embryos/larvae was significantly reduced at
all tested concentrations, making the low concentration of 0.05 mg/L
the lowest-observed-effect-concentration (LOEC) in this study; a no-
observed-effect-concentration (NOEC) was not established. Embryonic
malformation rate was significantly increased and larval growth
significantly decreased at >=0.1 mg/L. Malformations included epiboly
deformities, yolk sac and pericardial edema, tail and heart
malformations, swim bladder inflation, and spinal curvature. Embryo
hatching rate was reduced only at the high concentration of 1 mg/L.
Heart rate, a marker for cardiac developmental toxicity, was
significantly decreased at all tested concentrations. Associated
mechanistic studies suggest the mechanism for developmental toxicity
involves the generation of reactive oxygen species (ROS) and the
consequent triggering of apoptosis genes. Increased ROS formation
(indicative of oxidative stress) was observed at a nominal
concentration of 0.1 mg/L. In the same study, zebrafish embryos exposed
to HBCD exhibited increased expression of pro-apoptotic genes (Bax,
P53, Puma, Apaf-1, caspase 3, and caspase-9), decreased expression of
anti-apoptotic genes (Mdm2 and Bcl-2), and increased activity of
enzymes involved in apoptosis (caspase-3 and caspase-9) with LOECs of
0.05-1 mg/L.
    Hu et al. (Ref. 67) found that hatching of zebrafish embryos was
delayed at 0.002 mg/L, the lowest concentration tested, and other
concentrations up to and including 0.5 mg/L, but not the two high
concentrations of 2.5 and 10 mg/L. The same authors observed an
increase in heat shock protein (Hsp70) at 0.01 mg/L and an increase in
malondialdehyde activity, used as a measure of lipid peroxidation, at
0.5 mg/L. The activity of superoxide dismutase was increased at 0.1 mg/
L, but decreased at 2.5 and 10 mg/L. The authors concluded that HBCD
can cause oxidative stress and over expression of Hsp70 in acute
exposures of zebrafish embryos.
    Du et al. (Ref. 65) exposed zebrafish embryos 4 hours post-
fertilization to each of three diastereomers of HBCD ([alpha]-, [beta]-
, and [gamma]-HBCD) individually at nominal concentrations of 0.01,
0.1, and 1.0 mg/L. Hatching success was reduced after 68 hours of
exposure to [gamma]-HBCD at the lowest concentration (0.01 mg/L), but a
higher concentration of [alpha]- or [beta]-HBCD (0.1 mg/L) was
necessary to reduce hatching success. After 92 hours, survival was
reduced at concentrations of 0.01, 0.1, and 1 mg/L of [gamma]-, [beta]-
, and [alpha]-HBCD, respectively. Growth, measured as body length of
larvae after 92 hours of exposure, was reduced at 0.1 mg/L of [beta]-
and [gamma]-HBCD and at 1 mg/L of [alpha]-HBCD. After 116 hours of
exposure, malformations were observed at all test concentrations of
[beta]- and [gamma]-HBCD and at 0.1 mg/L and above for [alpha]-HBCD.
Effects on heart rate varied depending upon the length of exposure;
reduced heart rate was observed at 0.1 mg/L of [beta]- and [gamma]-HBCD
or 1 mg/L of [alpha]-HBCD at 44 hours and at 0.1 mg/L of [alpha]- and
[beta]-HBCD at 92 hours, whereas [gamma]-HBCD resulted in an increase
in heart rate at 1 mg/L at 92 hours. An increase in generation of ROS
was observed after 116 hours at 0.1 mg/L of [beta]- and [gamma]-HBCD
and at 1 mg/L of [alpha]-HBCD. Activities of caspase-3 and caspase-9
enzymes, indicative of apoptosis, were increased after 116 hours at 0.1
mg/L of [gamma]-HBCD and at 1 mg/L of [alpha]- and [beta]-HBCD. The
authors ranked the HBCD diastereomers in the following order for
developmental toxicity to zebrafish: [gamma]-HBCD > [beta] HBCD >
[alpha]-HBCD.
    Effects indicative of oxidative stress, as seen in the zebrafish
embryo studies, were also found in clams. Zhang et al. (Ref. 74)
measured parameters indicative of antioxidant defenses and oxidative
stress after 1, 3, 6, 10, and 15 days of exposure to low nominal
concentrations of HBCD ranging from 0.000086 to 0.0086 mg/L in the clam
Venerupis philippinarum. Increases in ethyoxyresorufin-o-deethylase
(EROD) activity, glutathione (GSH) content, and DNA damage were
observed in clams exposed to 0.00086 mg/L, while increased lipid
peroxidation (LPO) was observed at 0.0086 mg/L. These same effects were
observed at lower concentrations as the length of exposure increased.
    Anselmo et al. (Ref. 63) exposed sea urchin (Psammechinus miliaris)
embryos to HBCD in an early life stage test. Newly-fertilized embryos
were exposed to HBCD at nominal concentrations of 0, 9, 25, 50, and 100
nanomolar (nM) (0, 0.0058, 0.016, 0.032, and 0.064 mg/L, respectively)
in dimethyl sulfoxide solvent and evaluated at 72 hours post-
fertilization. A significant increase in morphological abnormalities
was found at a nominal concentration of 100 nM HBCD (0.064 mg/L), the
highest concentration tested. Observed malformations included short or
deformed larval arms and slight edema around the larval body. The NOEC
for this effect at 72 hours was 0.032 mg/L.
    2. Chronic aquatic toxicity. A measured MATC of 0.0042 mg/L, based
on reduced size (length) of surviving young water fleas (Daphnia
magna), indicates high chronic toxicity (Ref. 56). This study reported
additional effects, including decreased reproductive rate and decreased
mean weight of surviving young at 0.011 mg/L. Other effects reported
following chronic exposure to HBCD included degenerative changes in the
gills of clams (Macoma balthica), manifested by the increased frequency

of nuclear and nucleolar abnormalities and the occurrence of dead
cells, at nominal concentrations of >=0.1 mg/L (50-day LOEC) (Ref. 71),
a nominal MATC of 0.045 mg/L for increased morphological abnormalities
in sea urchin (P. miliaris) embryos exposed to HBCD for up to 16 days
in an early life stage test (Ref. 63), and a nominal MATC of 0.03 mg/L
for increased malformation rate in marine medaka (Oryzias melastigma)
embryos exposed to HBCD for 17 days in an early life stage test (Ref.
66). The developmental abnormalities in medaka included yolk sac edema,
pericardial edema, and spinal curvature (Ref. 66). Mechanistic findings
in this study included increases in heart rate and sinus venosus-bulbus
arteriosus (SV-BA) distance, which are markers for cardiac development,
induction of oxidative stress and apoptosis, and suppression of
nucleotide and protein synthesis.
    Thyroid effects were reported in juvenile rainbow trout
(Oncorhynchus mykiss) following dietary exposure to HBCD (Refs. 68 and
69). Each of the diastereomers of HBCD (administered separately via
diet at concentrations of 5 ng/g of [alpha]-, [beta]-, or [gamma]-HBCD
for up to 56 days) disrupted thyroid homeostasis, as indicated by lower
free circulating T3 and T4 levels.
    The mechanisms of the effects on fish and invertebrates following
chronic exposure were similar to those found in acute studies. Effects
observed in fish include increased formation of ROS resulting in
oxidative damage to lipids, proteins, and DNA, decreased antioxidant
capacities in fish tissue (e.g., brains, hepatocytes, or erythrocytes),
and increasing levels of EROD (detoxification enzyme) and
PentoxyResorufin-O-Deethylase (PROD, detoxification enzyme) levels in
hepatocytes of fish exposed to the nominal concentration of >=0.1 mg/L
(corresponds to ~0.2 mg/g whole fish (wet weight)) for 42 days (Ref.
73). Ronisz et al. (Ref. 70) found a significant increase in hepatic
cytosolic catalase activity in rainbow trout (Oncorhynchus mykiss) 5
days after a single intraperitoneal injection of 50 mg/kg was
administered. The same authors observed reductions in liver somatic
index (LSI) and EROD activity in a 28-day study in which rainbow trout
were injected intraperitoneally with HBCD on days 1 and 14 at a dose
somewhat less than 500 mg/kg. Zhang et al. (Ref. 74) observed the
following signs of oxidative stress in clams (V. philippinarum) after
15 days of exposure to HBCD: The activities of antioxidant enzymes
(EROD, superoxide dismutase (SOD), and glutathione-S-transferase
(GST)), as well as GSH content, were increased at 0.000086 mg/L, the
lowest concentration tested. In addition, LPO was increased at 0.00086
mg/L and DNA damage was increased at 0.0086 mg/L.
    3. Terrestrial toxicity and phytotoxicity. Japanese quail (Coturnix
coturnix japonica) exposed for 6 weeks to an isomeric mixture of HBCD
in the diet experienced a reduction in hatchability at all tested
concentrations (12-1,000 ppm) (Ref. 57). Additional effects included a
significant reduction in egg shell thickness starting at 125 ppm,
decreases in egg weights and egg production rates starting at 500 ppm,
increases in cracked eggs starting at 500 ppm, and adult mortality at
1,000 ppm. A subsequent test, conducted at lower dietary
concentrations, determined LOAEL and NOAEL values of 15 and 5 ppm,
respectively, based on significant reduction of survival of chicks
hatched from eggs of quails fed HBCD (Ref. 57).
    Several studies have been conducted examining effects of HBCD on
American kestrels (Falco sparverius). Kobiliris (Ref. 78) reported a
reduced ``corticosterone response'' (where ``corticosterone response''
was defined as a stimulation of the adrenal cortex to produce and
release corticosterone into the bloodstream), reduced flying activities
of juvenile males during hunting behavior trials, and delayed response
times of juvenile females during predator avoidance behavior trials in
American kestrels exposed in ovo to 164.13 ng/g wet weight. Kestrels
exposed via the diet to 0.51 mg/kg/day beginning 3 weeks prior to
pairing and continuing until the first chick hatched began to lay eggs
6 days earlier than controls and laid larger clutches of smaller eggs
(Ref. 59). Although the technical mixture of HBCD stereoisomers
contained predominantly [gamma]-HBCD (80% of the mixture), the main
isomer found in eggs was [alpha]-HBCD (>90% of the total HBCD in eggs).
In a subsequent study, Marteinson et al. (Ref. 61) exposed kestrels to
dietary HBCD at the same dose (0.51 mg/kg/day) and found increased
testes weight in unpaired males, a marginally significant effect on
testis histology in unpaired males (increased number of seminiferous
tubules containing elongated spermatids; p = 0.052), marginally
increased testosterone levels in breeding males (increased at the time
the first egg was laid; p = 0.054), and no significant effect on sperm
counts. Plasma T4 levels were reduced in breeding males throughout the
study, which the authors took to suggest that thyroid disruption that
may have contributed to the observed increase in testes weight.
Marteinson et al. (Ref. 62) found altered reproductive behavior in both
sexes of kestrels fed 0.51 mg/kg/day, including reduced activity in
both sexes during courtship and in males during brood rearing, which
may have contributed to the observed reduction in incubation nest
temperature and also to the reduced egg size reported previously by
Fernie et al. (Ref. 58). In a 22-day study of chickens (Gallus gallus
domesticus) exposed to HBCD in ovo, reduced pipping success was
observed at 100 ng/g egg (Ref. 79).
    The accumulation and toxicity of [alpha]-, [beta]-, and [gamma]-
HBCDs in maize have been studied (Ref. 80). The order of accumulation
in roots was [beta]-HBCD > [alpha]-HBCD > [gamma]-HBCD and in shoots it
was [beta]-HBCD > [gamma]-HBCD > [alpha]-HBCD. In maize exposed to 2
[mu]g/L HBCD, the inhibitory effect of the diastereomers on the early
development of maize as well as the intensities of hydroxyl radical and
histone H2AX phosphorylation followed the order [alpha]-HBCD > [beta]-
HBCD > [gamma]-HBCD, which indicates diastereomer-specific oxidative
stress and DNA damage in maize. The study confirmed that for maize
exposed to HBCDs, the generation of reactive oxygen species was one,
but not the only, mechanism for DNA damage.
    4. Conclusions regarding the ecological hazard potential of HBCD.
HBCD has been shown to cause acute toxicity to aquatic organisms at
concentrations as low as 0.009 mg/L and chronic toxicity at
concentrations as low as 0.0042 mg/L. Toxicity to terrestrial species
has been observed at doses as low as 0.51 mg/kg/day. The available
evidence shows that HBCD is highly toxic to aquatic and terrestrial
species.

C. What is EPA's review of the bioaccumulation data for HBCD?

    HBCD has been shown in numerous studies to bioaccumulate in aquatic
species and biomagnify in aquatic and terrestrial food chains (Ref. 1).
BCFs for HBCD in fish in the peer-reviewed literature range as high as
18,100 (Refs. 81, 82, and 83). Some of the bioaccumulation values for
fish species and a freshwater food web are shown in Table 1. The
complete listing of the available bioaccumulation data and more details
about the studies can be found in the ecological assessment (Ref. 1).

                         Table 1--HBCD BCF and BAF Data for Fish and Freshwater Food Web
----------------------------------------------------------------------------------------------------------------
                                      Duration and test
              Species                      endpoint                   Value                    Reference
----------------------------------------------------------------------------------------------------------------
Rainbow trout (Oncorhynchus         35-day BCF...........  8,974 and 13,085..........  Ref. 81.
 mykiss).
Fathead minnow (Pimephales          32-day BCF...........  18,100....................  Ref. 82.
 promelas).
Mirror carp (Cyprinus carpio        30-day exposure and    [alpha]-HBCD: 5,570-11,500  Ref. 83.
 morpha noblis).                     30-day depuration     [beta]-HBCD: 187-642......
                                     BCF.                  [gamma]-HBCD: 221-584.....
Mud carp (Cirrhinus molitorella),   Log BAF..............  4.8-7.7 for HBCD isomers    Ref. 84.
 nile tilapia (Tilapia nilotica),                           ([alpha][dash]HBCD had
 and suckermouth catfish                                    higher BAFs than [beta]-
 (Hypostomus plecostomus).                                  and [gamma][dash]HBCD)
                                                            (BAFs ranged from ~63,000
                                                            to 50,000,000).
Freshwater food web...............  Log BAF..............  [alpha]-HBCD: 2.58-6.01...  Ref. 85.
                                                           [beta]-HBCD: 3.24-5.58....
                                                           [gamma]-HBCD: 3.44-5.98...
                                                           [Sigma]HBCDs: 2.85-5.98...
                                                           (BAFs range from ~700 to
                                                            950,000).
----------------------------------------------------------------------------------------------------------------

    Drottar and Kruger (Ref. 81) provided strong evidence that HBCD
bioaccumulates in a study conducted according to established guidelines
(OECD Test Guideline (TG) 305 and Office of Prevention, Pesticides and
Toxic Substances (OPPTS) 850.1730). In this study, BCFs of 13,085 and
8,974 were reported in rainbow trout (O. mykiss) exposed to 0.18 and
1.8 [micro]g/L, respectively. Concentrations of HBCD in tissue reached
steady-state at day 14 for fish exposed to 1.8 [micro]g/L and, during
the subsequent depuration stage, a 50% reduction of HBCD from edible
and non-edible tissue and whole fish was reported on days 19 and 20
post-exposure. In fish exposed to 0.18 [micro]g/L, an apparent steady-
state was reached on day 21, but on day 35, the tissue concentration of
HBCD in fish increased noticeably; thus, steady-state was not achieved
according to study authors, and BCF values (for the exposure
concentration of 0.18 [micro]g/L) were calculated based on day 35
tissue concentrations. Clearance of 50% HBCD from tissue of 0.18
[micro]g/L exposed fish occurred 30-35 days post-exposure.
    Veith et al. (Ref. 82) further supports the conclusion that HBCD
bioaccumulates in a study conducted prior to the establishment of
standardized testing guidelines for bioconcentration studies. The study
reported a BCF of 18,100 following exposure of fathead minnows to 6.2
[micro]g/L; the BCF was identified as a steady-state BCF, but the
report does not indicate the time when steady-state was reached. A
depuration phase was not included in this study. Zhang et al. (Ref. 83)
calculated BCFs for each HBCD diastereomer in mirror carp and found
strong evidence that [alpha]-HBCD (BCF of 5,570-11,500) is much more
bioaccumulative than [beta]- and [gamma]-HBCD (BCF of 187-642); BCF
values that were normalized to lipid content were much higher (30,700-
45,200 for [alpha]-HBCD, 1,030-1,900 for [beta]-HBCD, and 950-1,730 for
[gamma]-HBCD) than non-normalized BCFs.
    BAFs, which capture accumulation of HBCD from diet as well as water
and sediment, were calculated for freshwater food webs in
industrialized areas of Southern China in two separate field studies.
He et al. (Ref. 84) calculated log BAFs of 4.8-7.7 (corresponding to
BAFs of 63,000-50,000,000) for HBCD isomers in carp, tilapia, and
catfish, and found higher BAFs for [alpha]-HBCD than [beta]- and
[gamma]-HBCD. In a pond near an e-waste recycling site, Wu et al. (Ref.
85) calculated log BAFs of 2.85-5.98 for HBCD (corresponding to BAFs of
700-950,000) in a freshwater food web. Log BAFs for each diastereomer
in this study were comparable to one another (see Table 1). La Guardia
et al. (Ref. 86) calculated log BAFs in bivalves and gastropods
collected downstream of a textile manufacturing outfall; these ranged
from 4.2 to 5.3 for [alpha]- and [beta]-HBCD (BAFs of 16,000-200,000),
and from 3.2 to 4.8 for [gamma]-HBCD (BAFs of 1,600-63,000).
    In general, [alpha]-HBCD bioaccumulates in organisms and
biomagnifies through food webs to a greater extent than the [beta]- and
[gamma]- diastereomers. Uncertainty remains as to the balance of
diastereomer accumulation in various species and the extent to which
bioisomerization and biotransformation rates for each isomer affect
bioaccumulation potential. Some authors (e.g., Law et al., Ref. 87)
have proposed that [gamma]-HBCD isomerizes to [alpha]-HBCD under
physiological conditions, rather than uptake being diastereisomer-
specific. To test this theory, Esslinger et al. (Ref. 88) exposed
mirror carp (Cyprinus carpio morpha noblis) to only [gamma]-HBCD and
found no evidence of bioisomerization. In contrast, when Du et al.
(Ref. 89) exposed zebrafish (Danio rerio) to only [gamma]-HBCD, they
found detectable levels of [alpha]-HBCD in fish tissue, suggesting that
bioisomerization occurred. Marvin et al. (Ref. 90) hypothesized that
differences in accumulation could also be due in part to a combination
of differences in solubility, bioavailability, and uptake and
depuration kinetics.
    Zhang et al. (Ref. 91) calculated diastereomer-specific BCFs in
algae and cyanobacteria ranging from 174 to 469. For the cyanobacteria
(Spirulina subsalsa), the BCF for [alpha]-HBCD (350) was higher than
the BCFs for [beta]-HBCD (270) and [gamma]-HBCD (174). However, for the
tested alga (Scenedesmus obliquus), the BCF for [beta]-HBCD (469) was
higher than that for the other isomers (390-407).
    In summary, HBCD has been shown in numerous studies to be highly
bioaccumulative in aquatic species and biomagnify in aquatic and
terrestrial food chains; however, diastereomer- and enantiomer-specific
mechanisms of accumulation are still unclear.

D. What is EPA's review of the persistence data for HBCD?

    There are limited data available on the degradation rates of HBCD
under environmental conditions. A short summary of the environmental
fate and persistence data for HBCD is presented in Table 2; additional
details about this data can be found in the HBCD hazard assessment
(Ref. 1).

               Table 2--Environmental Degradation of HBCD
------------------------------------------------------------------------
             Property                   Value             Reference
------------------------------------------------------------------------
                                   Air
------------------------------------------------------------------------
Photodegradation.................  Photo-induced    Ref. 9.2.
                                    isomerization
                                    of [gamma]-
                                    HBCD to
                                    [alpha]-HBCD
                                    in indoor dust
                                    with a
                                    measured
                                    decrease in
                                    HBCD
                                    concentration
                                    concurrent
                                    with an
                                    increase of
                                    pentabromocycl
                                    ododecenes
                                    (PBCDs) in
                                    indoor dust.
                                   Indirect         Ref. 93.
                                    photolysis
                                    half-life: 26
                                    hours AOPWIN
                                    v1.92
                                    (estimated).
------------------------------------------------------------------------
                                  Water
------------------------------------------------------------------------
Hydrolysis.......................  Not expected     Ref. 44.
                                    due to lack of
                                    functional
                                    groups that
                                    hydrolyze
                                    under
                                    environmental
                                    conditions and
                                    low water
                                    solubility
                                    (estimated).
------------------------------------------------------------------------
                                Sediment
------------------------------------------------------------------------
Aerobic conditions...............  No               Refs. 76 and 94.
                                    biodegradation
                                    observed in 28-
                                    day closed-
                                    bottle test.
                                   Half-life: 128,  Ref. 95.
                                    92, and 72
                                    days for
                                    [alpha]-,
                                    [gamma]-, and
                                    [beta]-HBCD,
                                    respectively
                                    (estimated),
                                    based on a 44%
                                    decrease in
                                    total initial
                                    radioactivity
                                    in viable
                                    freshwater
                                    sediment.
                                   Half-life: >120
                                    days
                                    (estimated),
                                    based on a 15%
                                    decrease in
                                    total initial
                                    radioactivity
                                    in abiotic
                                    freshwater
                                    sediment.
                                   Half-life: 11    Ref. 96.
                                    and 32 days
                                    (estimated) in
                                    viable
                                    sediment
                                    collected from
                                    Schuylkill
                                    River and
                                    Neshaminy
                                    creek,
                                    respectively.
                                   Half-life: 190
                                    and 30 days
                                    (estimated) in
                                    abiotic
                                    sediment
                                    collected from
                                    Schuylkill
                                    River and
                                    Neshaminy
                                    creek.
Anaerobic conditions.............  Half-life: 92    Ref. 95.
                                    days
                                    (estimated),
                                    based on a 61%
                                    decrease in
                                    total initial
                                    radioactivity
                                    in viable
                                    freshwater
                                    sediment.
                                   Half-life: >120
                                    days
                                    (estimated),
                                    based on a 33%
                                    decrease in
                                    total initial
                                    radioactivity
                                    in abiotic
                                    freshwater
                                    sediment.
                                   Half-life: 1.5   Ref. 96.
                                    and 1.1 days
                                    (estimated) in
                                    viable
                                    sediment
                                    collected from
                                    Schuylkill
                                    River and
                                    Neshaminy
                                    creek.
                                   Half-life: 10
                                    and 9.9 days
                                    (estimated) in
                                    abiotic
                                    sediment
                                    collected from
                                    Schuylkill
                                    River and
                                    Neshaminy
                                    creek.
------------------------------------------------------------------------
                                  Soil
------------------------------------------------------------------------
Aerobic conditions...............  Half-life: >120  Ref. 95.
                                    days
                                    (estimated),
                                    based on a 10%
                                    decrease in
                                    total initial
                                    radioactivity
                                    in viable soil.
                                   Half-life: >120
                                    days
                                    (estimated),
                                    based on a 6%
                                    decrease in
                                    total initial
                                    radioactivity
                                    in abiotic
                                    soil.
                                   Half-life: 63    Ref. 96.
                                    days
                                    (estimated) in
                                    viable soil
                                    amended with
                                    activated
                                    sludge.
                                   Half-life: >120
                                    days
                                    (estimated) in
                                    abiotic soil..
Anaerobic conditions.............  Half-life: 6.9   Ref. 96.
                                    days
                                    (estimated) in
                                    viable soil
                                    amended with
                                    activated
                                    sludge.
                                   Half-life: 82
                                    days
                                    (estimated) in
                                    abiotic soil
                                    using a
                                    nominal HBCD
                                    concentration
                                    of 0.025 mg/kg
                                    dry weight.
------------------------------------------------------------------------

    1. Abiotic degradation. HBCD is not expected to undergo significant
direct photolysis since it does not absorb radiation in the
environmentally available region of the electromagnetic spectrum that
has the potential to cause molecular degradation (Ref. 97). Although
HBCD is expected to exist primarily in the particulate phase in the
atmosphere, a small percentage may also exist in the vapor phase based
on its vapor pressure (Refs. 22, 90, 98, and 99). HBCD in the vapor
phase will be degraded by reaction with photochemically produced
hydroxyl radicals in the atmosphere. An estimated rate constant of 5.01
x 10-12 cubic centimeters (cm\3\)/molecules-second at 25
[deg]C for this reaction corresponds to a half-life of 26 hours,
assuming an atmospheric hydroxyl radical concentration of 1.5 x 10\6\
molecules/cm\3\ and a 12-hour day (Refs. 93 and 100).
    Photolytic isomerization of HBCD has been described in both indoor
dust samples and in samples of HBCD standards dissolved in methanol
using artificial light (Ref. 92). After 1 week in the presence of
light, indoor dust containing predominantly [gamma]-HBCD was found to
decrease in [gamma]-HBCD and increase in [alpha]-HBCD concentration.
There was a measured decrease in HBCD concentration concurrent with an
increase in PBCDs in the indoor dust exposed to artificial light. The
three diastereomerically-pure HBCD standards ([alpha]-, [beta]-, and
[gamma]-HBCD) that were dissolved in methanol also began to
interconvert within 1 week, resulting in a decrease in [gamma]-HBCD
concentration and an increase in [alpha]-HBCD concentration.
    HBCD is not expected to undergo hydrolysis in environmental waters
due to lack of functional groups that hydrolyze under environmental
conditions and the low water solubility of HBCD (Ref. 44).
    Observed abiotic degradation of HBCD during simulation tests based
on Organisation for Economic Cooperation and Development (OECD) methods
307 and 308 was approximately 33% in anaerobic freshwater sediment, 15%
in aerobic freshwater sediment, and 6% in aerobic soil after 112-113
days (Refs. 44 and 95). The results from these studies correspond to
estimated half-lives >120 days in soil and sediment due to minimal
degradation being observed. Initial concentrations of \14\C
radiolabeled HBCD ([alpha]-, [beta]-, and [gamma]- \14\C-HBCD in a
ratio of 7.74:7.84:81.5) were 3.0-4.7 mg/kg dry weight in the sediment
and soil systems. HBCD degradation observed under abiotic conditions
was attributed to abiotic reductive dehalogenation (Refs. 44, 76, and
95). Degradation proceeded through a stepwise process to form

tetrabromocyclododecene, dibromocyclododecadiene (DBCD), and 1,5,9-
cyclododecatriene (Refs. 44 and 95). Further degradation of 1,5,9-
cyclododecatriene was not observed. In this study, HBCD degradation
occurred faster in sediment than in soil and faster under anaerobic
conditions compared to aerobic conditions (Refs. 44 and 95).
    Previous OECD 308 and 307 based simulation tests from the same
authors (Davis et al. 2005, Ref. 96) presented results suggesting
faster abiotic degradation, particularly in sediment under anaerobic
conditions, but were performed at much lower HBCD concentrations and
measured only [gamma]-HBCD (Refs. 44, 76, 90, 96, and 101). In this
study, abiotic degradation half-lives in freshwater sediments were 30-
190 days under aerobic conditions and 9.9-10 days under anaerobic
conditions. Estimated half-lives in abiotic soil were >120 days under
aerobic conditions and 82 days under anaerobic conditions. This study
evaluated [gamma]-HBCD only and did not address interconversion of HBCD
isomers or [alpha]- and [beta]-HBCD degradation. The initial
concentrations of HBCD were 0.025-0.089 mg/kg dry weight in the
sediment and soil systems, nearly 100 times less than the HBCD
concentrations used in the subsequent Davis et al. 2006 study (Ref.
95). Higher concentrations of HBCD (3.0-4.7 mg/kg dry weight) in the
Davis et al. 2006 study (Ref. 95) allowed for quantification of
individual isomers, metabolite identification and mass balance
evaluation (Refs. 95 and 101). Additionally, the Davis et al. 2005
study (Ref. 96) was considered to be of uncertain reliability for
quantifying HBCD persistence because of concerns regarding potential
contamination of sediment samples, an interfering peak corresponding to
[gamma]-HBCD in the liquid chromatography/mass spectrometry (LC/MS)
chromatograms, and poor extraction of HBCD leading to HBCD recoveries
of 33-125% (Refs. 44 and 101).
    2. Biotic degradation. A few studies on the biodegradation of HBCD
were located. A closed bottle screening-level test for ready
biodegradability (OECD Guideline 301D, EPA OTS 796.3200) was performed
using an initial HBCD concentration of 7.7 mg/L and an activated
domestic sludge inoculum (Refs. 76 and 94). No biodegradation was
observed (0% of the theoretical oxygen demand) over the test period of
28 days under the stringent guideline conditions of this test.
    Degradation of HBCD during simulation tests with viable microbes,
based on OECD methods 307 and 308, was approximately 61% in anaerobic
freshwater sediment, 44% in aerobic freshwater sediment, and 10% in
aerobic soil after 112-113 days (Refs. 44 and 95). The results from
this study correspond to estimated HBCD half-lives of 92 days in
anaerobic freshwater sediment, 128, 92, and 72 days for [alpha]-,
[gamma]-, and [beta]-HBCD, respectively in aerobic freshwater sediment,
and >120 days in aerobic soil. An initial total \14\C-HBCD
concentration of 3.0-4.7 mg/kg dry weight in the sediment and soil
systems was used, allowing for quantification of individual isomers,
metabolite identification, and mass balance evaluation (Refs. 95 and
101). Although very high spiking rates can be toxic to microorganisms
in biodegradation studies and lead to unrealistically long estimated
half-lives, the results of this study did not suggest toxicity to
microorganisms. Tests with viable microbes demonstrated increased HBCD
degradation compared to the biologically-inhibited control studies. In
combination, these studies suggest that HBCD will degrade slowly in the
environment, although faster in sediment than in soil, faster under
anaerobic conditions than aerobic conditions, faster with microbial
action than without microbial action, and at different rates for
individual HBCD diastereomers (slower for [alpha]-HBCD than for the
[gamma]- and [beta]-stereoisomers).
    The same researchers (Ref. 76) previously conducted a water-
sediment simulation test for commercial HBCD based on OECD guideline
308 using nominal HBCD concentrations of 0.034-0.089 mg/kg dry weight
(Refs. 44, 76, and 102). Aerobic and anaerobic microcosms were pre-
incubated at 20 [deg]C for 49 days and at 23 [deg]C for 43-44 days,
respectively. HBCD was then added to 14-37 g dry weight freshwater
sediment samples in 250 ml serum bottles (water:sediment ratio of 1.6-
2.9) and the microcosms were sealed and incubated in the dark at 20
[deg]C for up to 119 days. For the aerobic microcosms, the headspace
oxygen concentration was kept above 10-15%. This study evaluated only
[gamma]-HBCD and did not address interconversion of HBCD isomers or
[alpha]- and [beta]-HBCD degradation. Disappearance half-lives of HBCD
with sediment collected from Schuylkill River and Neshaminy creek were
11 and 32 days in viable aerobic sediments, respectively (compared to
190 and 30 days in abiotic aerobic controls, respectively), and 1.5 and
1.1 days in viable anaerobic sediments, respectively (compared to 10
and 9.9 days in abiotic anaerobic controls).
    Data from these tests suggest that anaerobic degradation is faster
than aerobic degradation of HBCD in viable and abiotic sediments and
that degradation is faster in viable conditions than abiotic
conditions. While these findings are consistent with Davis et al. 2006
(Ref. 95), the actual degradation rates in this study are much faster.
However, results from this study do not provide a reliable indication
of HBCD persistence. A mass balance could not be established because
only [gamma]-HBCD was used to quantify HBCD concentrations, \14\C-
radiolabelled HBCD was not used, and degradation products were not
identified; therefore, apparent disappearance of HBCD in this study may
not reflect biodegradation. In addition, there were concerns that
contaminated sediment may have been used, HBCD extraction was
incomplete (HBCD recovery varied from 33 to 125%), and an interfering
peak was observed in the LC/MS chromatograms corresponding to [gamma]-
HBCD (Refs. 44 and 101).
    Similarly, a soil simulation test was conducted based on OECD
guideline 307 for commercial HBCD using 50 g dry weight sandy loam soil
samples added to 250 ml serum bottles (Refs. 44, 76, 96, and 103). The
moisture content was 20% by weight. Aerobic and anaerobic microcosms
were pre-incubated at 20 [deg]C for 35 days and at 23 [deg]C for 43
days, respectively. Activated sludge was added to the soil at 5 mg/g,
and HBCD was added to the soil to achieve a nominal concentration of
0.025 mg/kg dry weight. The microcosms were then incubated in the dark
at 20 [deg]C for up to 120 days. The disappearance half-lives were 63
days in viable aerobic soil (compared to >120 days in abiotic aerobic
controls) and 6.9 days in viable anaerobic soil (compared to 82 days in
abiotic anaerobic controls). As in the sediment studies, HBCD
degradation in soil occurred faster under anaerobic conditions compared
to aerobic conditions, and faster in viable conditions than abiotic
conditions. The disappearance half-lives in soil were slower than those
in sediment.
    Biological processes were suggested to be responsible for the
increased degradation of HBCD in this study using viable conditions,
relative to abiotic conditions; however, degradation was not adequately
demonstrated in soil because no degradation products were detected and
only [gamma]-HBCD was used to quantify HBCD concentrations, making it
impossible to calculate a mass balance. HBCD recoveries on day 0 of the
experiment were well below (0.011-0.018 mg/kg dry weight) the nominal
test concentrations (0.025 mg/kg dry weight), suggesting rapid
adsorption of HBCD to soil and poor extraction methods (Refs. 44 and
101).

    In studies using 0.025-0.089 mg/kg HBCD (Davis et al. 2005, Ref.
96), the estimated half-life values were shorter than studies using
3.0-4.7 mg/kg HBCD (Davis et al. 2006, Ref. 95) by approximately one
order of magnitude for aerobic viable sediment (11-32 days compared
to72-128 days) and anaerobic viable sediment (1.1-1.5 days compared to
92 days). The viable aerobic soil half-life using lower concentrations
of HBCD (Davis et al. 2005, Ref. 96) was less than half of the half-
life based on the higher HBCD concentration (63 days compared to >120
days) (Davis et al. 2006, Ref. 95). Both Davis et al. studies (Refs. 95
and 96) suggest that HBCD degrades faster in sediment than in soil,
faster under anaerobic conditions than aerobic conditions, and faster
with microbial action than without microbial action. HBCD is poorly
soluble, and it was suggested that at higher concentrations of HBCD,
degradation is limited by mass transfer of HBCD into microbes. However,
results from the Davis et al. 2005 study (Ref. 96) likely overestimate
the rate of HBCD biodegradation, for the reasons noted previously
(primarily, failure to use \14\C-radiolabelled HBCD, quantify isomers
other than [gamma]-HBCD, identify degradation products, or establish a
mass balance, but also procedural problems with contamination of
sediment, incomplete HBCD extraction, and occurrence of an interfering
peak in the LC/MS chromatograms corresponding to [gamma]-HBCD).
    It is important to note that the rapid biodegradation rates from
Davis et al. 2005 (Ref. 96) are not consistent with environmental
observations. HBCD has been detected over large areas and in remote
locations in environmental monitoring studies (Refs 1 and 104). Dated
sediment core samples indicate slow environmental degradation rates
(Refs. 44, 90, 96, and 101). For example, HBCD was found at
concentrations ranging from 112 to 70,085 [mu]g/kg dry weight in
sediment samples collected at locations near a production site in
Aycliffe, United Kingdom two years after the facility was closed down
(Ref. 44). Monitoring data do not provide a complete, quantitative
determination of persistence because HBCD emission sources, rates, and
quantities are typically unknown, and all environmental compartments
are not considered. However, the monitoring data do provide evidence in
support of environmental persistence. In addition, the widespread
presence of HBCD in numerous terrestrial and aquatic species indicates
persistence in the environment sufficient for bioaccumulation to occur
(Ref. 1).

IV. Rationale for Listing HBCD and Lowering the Reporting Threshold

A. What is EPA's rationale for listing the HBCD category?

    HBCD has been shown to cause developmental effects at doses as low
as 146.3 mg/kg/day (LOAEL) in male rats. Developmental effects have
also been observed with a BMDL of 0.056 mg/kg/day (BMD of 0.18 mg/kg/
day) based on effects in female rats and a BMDL of 0.46 mg/kg/day (BMD
of 1.45 mg/kg/day) based on effects in male rats. HBCD also causes
reproductive toxicity at doses as low 138 mg/kg/day (LOAEL) in female
rats. Based on the available developmental and reproductive toxicity,
EPA believes that HBCD can be reasonably anticipated to cause
moderately high to high chronic toxicity in humans. Therefore, EPA
believes that the evidence is sufficient for listing the HBCD category
on the EPCRA section 313 toxic chemical list pursuant to EPCRA section
313(d)(2)(B) based on the available developmental and reproductive
toxicity data.
    HBCD has been shown to be highly toxic to both aquatic and
terrestrial species with acute aquatic toxicity values as low as 0.009
mg/L and chronic aquatic toxicity values as low as 0.0042 mg/L. HBCD is
highly toxic to terrestrial species as well with observed toxic doses
as low as 0.51 and 2.1 mg/kg/day. In addition to being highly toxic,
HBCD is also bioaccumulative and persistent in the environment, which
further supports a high concern for the toxicity to aquatic and
terrestrial species. EPA believes that HBCD meets the EPCRA section
313(d)(2)(C) listing criteria on toxicity alone but also based on
toxicity and bioaccumulation as well as toxicity and persistence in the
environment. Therefore, EPA believes that the evidence is sufficient
for listing the HBCD category on the EPCRA section 313 toxic chemical
list pursuant to EPCRA section 313(d)(2)(C) based on the available
ecological toxicity data as well as the bioaccumulation and persistence
data.
    HBCD has the potential to cause developmental and reproductive
toxicity at moderately low to low doses and is highly toxic to aquatic
and terrestrial organisms; thus, EPA considers HBCD to have moderately
high to high chronic human health toxicity and high ecological
toxicity. EPA does not believe that it is appropriate to consider
exposure for chemicals that are moderately high to highly toxic based
on a hazard assessment when determining if a chemical can be added for
chronic human health effects pursuant to EPCRA section 313(d)(2)(B)
(see 59 FR 61440-61442). EPA also does not believe that it is
appropriate to consider exposure for chemicals that are highly toxic
based on a hazard assessment when determining if a chemical can be
added for environmental effects pursuant to EPCRA section 313(d)(2)(C)
(see 59 FR 61440-61442). Therefore, in accordance with EPA's standard
policy on the use of exposure assessments (See November 30, 1994 (59 FR
61432, FRL-4922-2), EPA does not believe that an exposure assessment is
necessary or appropriate for determining whether HBCD meets the
criteria of EPCRA section 313(d)(2)(B) or (C).

B. What is EPA's rationale for lowering the reporting threshold for
HBCD?

    EPA believes that the available bioaccumulation and persistence
data for HBCD support a classification of HBCD as a PBT chemical. HBCD
has been shown to be highly bioaccumulative in aquatic species and to
also biomagnify in aquatic and terrestrial food chains. While there is
limited data on the half-life of HBCD in soil and sediment, the best
available data supports a determination that the half-life of HBCD in
soil and sediment is at least 2 months. This determination is further
supported by the data from environmental monitoring studies, which
indicate that HBCD has significant persistence in the environment. The
widespread presence of HBCD in numerous terrestrial and aquatic species
also supports the conclusion that HBCD has significant persistence in
the environment. Therefore, consistent with EPA's established policy
for PBT chemicals (See 64 FR 58666, October 29, 1999) (FRL-6389-11) EPA
is proposing to establish a 100-pound reporting threshold for the HBCD
category.

V. References

    The following is a listing of the documents that are specifically
referenced in this document. The docket includes these documents and
other information considered by EPA, including documents that are
referenced within the documents that are included in the docket, even
if the referenced document is not itself physically located in the
docket. For assistance in locating these other documents, please
consult the person listed under FOR FURTHER INFORMATION CONTACT.

1. USEPA, OEI. 2016. Technical Review of Hexabromocyclododecane
(HBCD) CAS

Registry Numbers 3194-55-6 and 25637-99-4. January 25, 2016.
2. USEPA, OEI. 2014. Economic Analysis of the Proposed Rule to add
HBCD to the List of TRI Reportable Chemicals. March 28, 2014.
3. Arita, R., Miyazaki, K., Mure, S. 1983. Metabolic test of HBCD.
Test on chemical substances used in household items. Studies on
pharmacodynamics of HBCD (unpublished). In: Toxicology summary: HBCD
(HBCD), Albemarle, S.A. Department of Pharmacy, Hokkaido University
Hospital, Japan.
4. Yu, C.C., Atallah, Y.H. 1980. Pharmacokinetics of HBCD in rats
(unpublished). Vesicol Chemical Corporation, Rosemont, IL.
5. Szabo, D.T., Diliberto, J.J., Hakk, H. et al. 2010.
Toxicokinetics of the flame retardant HBCD gamma: Effect of dose,
timing, route, repeated exposure, and metabolism. Toxicol. Sci.
117(2):282-293.
6. Szabo, D.T., Diliberto, J.J., Hakk, H., Huwe, J.K., Birnbaum,
L.S. 2011. Toxicokinetics of the flame retardant
hexabromocyclododecane alpha: Effect of dose, timing, route,
repeated Exposure, and metabolism. Toxicol. Sci. 121(2):234-244.
7. Reistad, T., Fonnum, F., Mariussen, E. 2006. Neurotoxicity of the
pentabrominated diphenyl ether mixture, DE-71, and HBCD (HBCD) in
rat cerebellar granule cells in vitro. Arch. Toxicol. 80(11):785-
796.
8. van der Ven, L.T.M., Verhoef, A., van de Kuil, T., Slob, W.,
Leonards, P.E.G., Visser, T.J., Hamers, T., Herlin, M., Hakansson,
H., Olausson, H., Piersma, A.H., Vos, J.G. 2006. A 28-day oral dose
toxicity study enhanced to detect endocrine effects of
hexabromocyclododecane in Wistar rats. Toxicological Sciences 94(2):
281-292.
9. van der Ven, L.T.M., van de Kuil, T., Leonards, P.E., et al.
2009. Endocrine effects of HBCD (HBCD) in a one-generation
reproduction study in Wistar rats. Toxicol Lett 185:51-62. Including
supplementary tables.
10. Brandsma, S.H., van der Ven, L.T.M., De Boer, J. and Leonards,
P.E. 2009. Identification of hydroxylated metabolites of
hexabromocyclododecane in wildlife and 28-days exposed Wistar rats.
Environ. Sci. Technol. 43, 6058-6063.
11. Hakk, H., Szabo, D.T., Huwe, J., Diliberto, J. and Birnbaum,
L.S. 2012. Novel and distinct metabolites identified following a
single oral dose of [alpha]- or [gamma]-hexabromocyclododecane in
mice. Environ. Sci. Technol. 46:13494-13503.
12. Sanders, J.M., Knudsen, G.A. and Birnbaum, L.S. 2013. The fate
of [beta]-hexabromocyclododecane in female C57BL/6 mice.
Toxicological Sciences 134(2): 251-257.
13. Antignac, J.P., Cariou, R., Maume, D., et al. 2008. Exposure
assessment of fetus and newborn to brominated flame retardants in
France: preliminary data. Mol. Nutr. Food Res. 52(2):258-265.
14. Weiss, J., Wallin, E., Axmon, A., et al. 2006. Hydroxy-PCBs,
PBDEs, and HBCDDs in serum from an elderly population of Swedish
fishermen's wives and associations with bone density. Environ. Sci.
Technol. 40(20):6282-6289.
15. Kakimoto, K., Akutsu, K., Konishi, Y., et al. 2008. Time trend
of HBCD in the breast milk of Japanese women. Chemosphere
71(6):1110-1114.
16. Rawn, D.F.K., Ryan, J.J., Sadler, A.R. et al. 2014. Brominated
flame retardant concentrations in sera from the Canadian Health
Measures Survey (CHMS) from 2007 to 2009. Environment International
63: 26-34.
17. Abdallah, M. and Harrad, S. 2011. Tetrabromobisphenol-A,
hexabromocyclododecane and its degradation products in UK human
milk: Relationship to external exposure. Environment International,
37: 443-448.
18. Meijer, L., Weiss, J., Van Velzen, M., et al. 2008. Serum
concentrations of neutral and phenolic organohalogens in pregnant
women and some of their infants in The Netherlands. Environ. Sci.
Technol. 42(9):3428-3433.
19. Thomsen, C., Molander, P., Daae, H.L., et al. 2007. Occupational
exposure to HBCD at an industrial plant. Environ. Sci. Technol.
41(15):5210-5216.
20. Fangstrom, B., Strid, A., Bergman, A. 2005. Temporal trends of
brominated flame retardants in milk from Stockholm mothers, 1980-
2004. Department of Environmental Chemistry, Stockholm University,
Stockholm, Sweden. Available online at: http://www.imm.ki.se/Datavard/PDF/mj%C3%B6lk_poolade_NV%20rapport%202005%20modersmjolk.pdf.
21. Fangstrom, B., Athanassiadis, I., Odsjo, T., et al. 2008.
Temporal trends of polybrominated diphenyl ethers and HBCD in milk
from Stockholm mothers, 1980-2004. Mol. Nutr. Food Res. 52(2):187-
193.
22. Covaci, A., Gerecke, A.C., et al. 2006. Hexabromocyclododecanes
(HBCDs) in the Environment and Humans: A Review. Environ. Sci.
Technol. 40: 3679-3688.
23. Johnson-Restrepo, B., Adams, D.H., et al. 2008.
Tetrabromobisphenol A (TBBPA) and Hexabromocyclododecanes (HBCDs) in
tissues of humans, dolphins, and sharks from the United States.
Chemosphere 70: 1935-1944.
24. Toms, L-M.L., Guerra, P., Eljarrat, E., Barcel[oacute], D.,
Harden, F.A., Hobson, P., et al. 2012. Brominated flame retardants
in the Australian population: 1993-2009. Chemosphere 89:398-403.
25. Schecter, A., Szabo, D.T., Miller, J., Gent, T.L., Malik-Bass,
N., Petersen, M., Paepke, O., Colacino, J.A., Hynan L.S., Harris,
T.R., Malla, S., Birnbaum, L.S. 2012. Hexabromocyclododecane (HBCD)
stereoisomers in U.S. food from Dallas, TX. Environmental Health
Perspectives 120(9): 1260-1264.
26. IRDC (International Research and Development Corporation). 1977.
Acute toxicity studies in rabbits and rats with HBCD with
attachments. Submitted under TSCA Section 8E; EPA Document No. 88-
7800065; NTIS No. OTS0200051.
27. IRDC (International Research and Development Corporation). 1978.
Acute toxicity studies in rabbits and rats with residue of HBCD with
attachments and cover letter dated 030178. Submitted under TSCA
Section 8E; EPA Document No. 88-7800088; NTIS No. OTS0200466.
28. Pharmakon Research International Inc. 1990. Acute exposure oral
toxicity study in rats (83 EPA/OECD) with attachments and cover
letter dated 030890. Submitted under TSCA Section 8D; EPA Document
No. 86-900000166; NTIS No. OTS0522237.
29. Gulf South Research Institute. 1988. Initial submission: Letter
from Ethyl Corp to USEPA regarding technical and toxicity data on
brominated flame retardants including HBCD. EPA Document No. FYI-
OTS-0794-0947; NTIS No. OTS0000947.
30. BASF. 1990. Report on the study of the acute oral toxicity of
HBCD in the mouse with cover letter dated 03-12-90. Submitted under
TSCA Section 8D; EPA Document No. 86-900000383; NTIS No. OTS0522946.
31. Lewis, A.C., Palanker, A.L. 1978. A dermal LD50 study
in albino rabbits and an inhalation LC50 study in albino
rats. Test material GLS-S6-41A (unpublished). Consumer Product
Testing, Fairfield, NJ; Experiment Reference No. 78385-2. Client:
Saytech Inc.
32. Momma, J., Kaniwa, M., Sekiguchi, H., Ohno, K., Kawasaki, Y.,
Tsuda, M., Nakamura, A., Kurokawa, Y. 1993. Dermatological
evaluation of a flame retardant, hexabromocyclododecane (HBCD) on
guinea pig by using the primary irritation, sensitization,
phototoxicity, and photosensitization of skin. (Article in Japanese;
English abstract). Eisei Shikenjo Hokoku 111:18-24.
33. Chengelis, C. 1997. A 28-day repeated dose oral toxicity study
of HBCD in rats. Study No. WIL-186004. WIL Research Laboratories,
Inc. Ashland, OH.
34. Chengelis, C. 2001. An oral (gavage) 90-day toxicity study of
HBCD in rats. Study No. WIL-186012. WIL Research Laboratories, Inc.
Ashland, Ohio.
35. Chengelis, C. 2002. Amendment to the Final Report for: An oral
(gavage) 90-day toxicity study of HBCD in rats. Study No. WIL-
186012. WIL Research Laboratories, Inc. Ashland, Ohio.
36. Hill, R.N., Crisp, T.M., Hurley, P.M., Rosenthal, S.L., and
Singh, D.V. 1998. Risk assessment of thyroid follicular cell tumors.
Environ. Health Perspect. 106, 447-457.
37. Zeller, H. and Kirsch, P. 1969. Hexabromocyclododecane: 28-day
feeding trials with rats. BASF unpublished laboratory study. As
cited in USEPA. 2001. High Production Volume (HPV) data summary and
test plan for hexabromocyclododecane (HBCD) CAS No. 3194-55-6.
Prepared by the American Chemistry Council's Brominated Flame
Retardant Industry Panel (BFRIP), Arlington, VA.
38. Zeller, H. and Kirsch, P. 1970. Hexabromocyclododecane: 90-day

feeding trials with rats. BASF unpublished laboratory study. As
cited in USEPA. 2001. High Production Volume (HPV) data summary and
test plan for hexabromocyclododecane (HBCD) CAS No. 3194-55-6.
Prepared by the American Chemistry Council's Brominated Flame
Retardant Industry Panel (BFRIP), Arlington, VA.
39. Kurokawa, Y., Inoue, T., Uchida, Y., et al. 1984. Carcinogenesis
test of flame retarder hexabromocyclododecane in mice. Hardy, M.;
Albemarle Corporation, personal communication, Department of
Toxicology, National Public Health Research Institute, Biological
Safety Test Research Center. Unpublished, translated from Japanese.
As cited in reference 40.
40. USEPA. 2014. Flame Retardant Alternatives for
Hexabromocyclododecane (HBCD): Final Report.
41. Saegusa, Y., Fujimoto, H., Woo, G., et al. 2009. Developmental
toxicity of brominated flame retardants, tetrabromobisphenol A and
1,2,5,6,9,10-HBCD, in rat offspring after maternal exposure from
mid-gestation through lactation. Reprod. Toxicol. 28(4):456-67.
42. Ema, M., Fujii, S., Hirata-Koizumi, M., et al. 2008. Two-
generation reproductive toxicity study of the flame retardant HBCD
in rats. Reprod. Toxicol. 25(3):335-351.
43. Murai, T., Kawasaki, H., Kanoh, S. 1985. Studies on the toxicity
of insecticides and food additives in pregnant rats (7). Fetal
toxicity of HBCD. Oyo Yakuri (Pharmacometrics) 29:981-986 (in
Japanese with English abstract).
44. European Commission. 2008. Risk Assessment:
Hexabromocyclododecane CAS-No.: 25637-99-4 EINECS No.: 247-148-4,
Final Report May 2008. Luxembourg: Office for Official Publications
of the European Communities.
45. Eriksson, P., Fischer, C., Wallin, M., et al. 2006. Impaired
behaviour, learning and memory, in adult mice neonatally exposed to
HBCD (HBCDD). Environ. Toxicol. Pharmacol. 21(3):317-322.
46. USEPA. 1998. Guidelines for neurotoxicity risk assessment. Risk
Assessment Form. Federal Register. 63 FR 26926, May 14, 1998 (FRL-
6011-3).
47. Industrial Bio-Test Labs. 1990. Mutagenicity of two lots of FM-
100 lot 53 and residue of lot 3322 in the absence and presence of
metabolic activation with test data and cover letter. Submitted
under TSCA Section 8D; EPA Document No. 86-900000267; NTIS No.
OTS0523259.
48. Litton Bionetics Inc. 1990. Mutagenicity evaluation of 421-32b
(Final report) with test data and cover letter. Submitted under TSCA
Section 8D; EPA Document No. 86-900000265; NTIS No. OTS0523257.
49. SRI Research Institute. 1990. In vitro microbiological
mutagenicity studies of four CIBA-GEIGY corporation compounds (Final
report) with test data and cover letter. Submitted under TSCA
Section 8D; EPA Document No. 86-900000262; NTIS No. OTS0523254.
50. Zeiger, E., Anderson, B., Haworth, S., et al. 1987. Salmonella
mutagenicity tests: III. Results from the testing of 255 chemicals.
Environ. Mutagen. 9 (Suppl. 9):1-110.
51. Huntingdon Research Center. 1978. Ames metabolic activation test
to assess the potential mutagenic effect of compound no. 49 with
cover letter dated 031290. Submitted under TSCA Section 8D; EPA
Document No. 86-900000385; NTIS No. OTS0522948.
52. Pharmakologisches Institute. 1978. Ames test with hexabromides
with cover letter dated 031290. Submitted under TSCA Section 8D; EPA
Document No. 86-900000379; NTIS No. OTS0522942.
53. Ethyl Corporation. 1985. Genetic toxicology Salmonella/
microsomal assay on HBCD with cover letter dated 030890. Submitted
under TSCA Section 8D; EPA Document No. 86-900000164; NTIS No.
OTS0522235.
54. Microbiological Associates Inc. 1996. HBCD (HBCD): chromosome
aberrations in human peripheral blood lymphocytes with cover letter
dated 12/12/1996. Submitted under TSCA Section 8D; EPA Document No.
86970000358; NTIS No. OTS0573552.
55. Walsh, G.E., Yoder, M.J., McLaughlin, L.L., et al. 1987.
Responses of marine unicellular algae to brominated organic
compounds in six growth media. Ecotoxicol. Environ. Saf. 14:215-222.
56. Drottar, K.R., Krueger, H.O. 1998. Hexabromocyclododecane
(HBCD): A flow-through life-cycle toxicity test with the cladoceran
(Daphnia magna). Report #439A-108. Wildlife International Ltd,
Easton, MD, pp 78. Submitted under TSCA Section 8D; EPA Document No.
86980000152; OTS0559490.
57. MOEJ (Ministry of the Environment, Japan). 2009. 6-Week
administration study of 1,2,5,6,9,10-hexabromocyclododecane for
avian reproduction toxicity under long-day conditions using Japanese
quail. Report. Ministry of the Environment, Japan. Research
Institute for Animal Science in Biochemistry & Toxicology (as cited
in Ref. 58).
58. UNEP (United Nations Environmental Program). 2010.
Hexabromocyclododecane draft risk profile. United Nations
Environmental Program, Stockholm Convention.
59. Fernie, K.J., Marteinson, S.C., Bird, D.M., et al. 2011.
Reproductive changes in American kestrels (Falco sparverius) in
relation to exposure to technical hexabromocyclododecane flame
retardant. Environ. Toxicol. Chem. 30:2570-2575.
60. Marteinson, S.C., Bird, D.M., Shutt, J.L., et al. 2010. Multi-
generational effects of polybrominated diphenylethers exposure:
Embryonic exposure of male American kestrels (Falco sparverius) to
DE-71 alters reproductive success and behaviors. Environ. Toxicol.
Chem. 29: 1740-1747.
61. Marteinson, S.C., Kimmins, S., Letcher, R.J., et al. 2011. Diet
exposure to technical hexabromocyclododecane (HBCD) affects testes
and circulating testosterone and thyroxine levels in American
kestrels (Falco sparverius). Environ. Res. 111:1116-1123.
62. Marteinson, S.C., Bird, D.M., Letcher, R.J., et al. 2012.
Dietary exposure to technical hexabromocyclododecane (HBCD) alters
courtship, incubation and parental behaviors in American kestrels
(Falco sparverius). Chemosphere 89:1077-1083.
63. Anselmo, H.M.R., Koerting, L., Devito, S., et al. 2011. Early
life developmental effects of marine persistent organic pollutants
on the sea urchin Psammechinus miliaris. Ecotox. Environ. Safe.
74:2182-2192.
64. Deng, J., Yu, L., Liu, C., et al. 2009. Hexabromocyclododecane-
induced developmental toxicity and apoptosis in zebrafish embryos.
Aquat. Toxicol. 93(1):29-36.
65. Du, M., Zhang, D., Yan, C., et al. 2012. Developmental toxicity
evaluation of three hexabromocyclododecane diastereoisomers on
zebrafish embryos. Aquat. Toxicol. 112-113:1-10.
66. Hong, H., Li, D., Shen, R., et al. 2014. Mechanisms of
hexabromocyclododecanes induced developmental toxicity in marine
medaka (Oryzias melastigma) embryos. Aquat. Toxicol. 152:173-185.
67. Hu, J., Liang, Y., Chen, M., et al. 2009. Assessing the toxicity
of TBBPA and HBCD by zebrafish embryo toxicity assay and biomarker
analysis. Environ. Toxicol. 24:334-342.
68. Palace, V.P., Pleskach, K., Halldorson, T., et al. 2008.
Biotransformation enzymes and thyroid axis disruption in juvenile
rainbow trout (Oncorhynchus mykiss) exposed to
hexabromocyclododecane diastereoisomers. Environ. Sci. Technol.
42(6):1967-1972.
69. Palace, V., Park, B., Pleskach, K., et al. 2010. Altered
thyroxine metabolism in rainbow trout (Oncorhynchus mykiss) exposed
to hexabromocyclododecane (HBCD). Chemosphere 80(2):165-169.
70. Ronisz, D., Farmen Finne, E., Karlsson, H., et al. 2004. Effects
of the brominated flame retardants hexabromocyclododecane (HBCDD),
and tetrabromobisphenol A (TBBPA), on hepatic enzymes and other
biomarkers in juvenile rainbow trout and feral eelpout. Aquat.
Toxicol. 69:229-245.
71. Smolarz, K. and Berger, A. 2009. Long-term toxicity of
hexabromocyclododecane (HBCDD) to the benthic clam Macoma balthica
(L.) from the Baltic Sea. Aquat. Toxicol. 95(3):239-247.
72. Wu, M., Zuo, Z., Li, B., et al. 2013. Effects of low-level
hexabromocyclododecane (HBCD) exposure on cardiac development in
zebrafish embryos. Ecotoxicology 22:1200-1207.
73. Zhang, X., Yang, F., Zhang, X., et al. 2008. Induction of
hepatic enzymes and oxidative stress in Chinese rare minnow
(Gobiocypris rarus) exposed to waterborne hexabromocyclododecane
(HBCDD). Aquat. Toxicol. 86(1):4-11.
74. Zhang, H., Pan, L., Tao, Y. 2014. Antioxidant responses in clam

Venerupis philippinarum exposed to environmental pollutant
hexabromocyclododecane. Environ. Sci. Pollut. Res. 21:8206-8215.
75. Desjardins, D., MacGregor, J.A., Krueger, H.O. 2004.
Hexabromocyclododecane (HBCD): A 72 hour toxicity test with the
marine diatom (Skeletonema costatum), Final report. Wildlife
Internation Ltd, Easton, MD, pp 66. As cited in Refs. 44 and 76.
76. IUCLID. 2005. Hexabromocyclododecane IUCLID dataset. Submitted
to U.S. EPA's High Production Volume (HPV) Chemical Program.
77. Desjardins, D., MacGregor, J.A., Krueger, H.O. 2005. Final
report. Chapter 1, Hexabromocyclododecane (HBCD): A 72-hour toxicity
test with the marine diatom (Skeletonema costatum) using a co-
solvent. Chapter 2, Hexabromocyclododecane (HBCD): A 72-hour
toxicity test with the marine diatom (Skeletonema costatum) using
generator column saturated media. Wildlife International Ltd,
Easton, MD, pp19. As cited in Ref. 44.
78. Kobiliris, D. 2010. Influence of embryonic exposure to
hexabromocyclododecane (HBCD) on the corticosterone response and
``fight or flight'' behaviors of captive American kestrels. Thesis
submitted to McGill University in partial fulfilment of the
requirements of the degree of Masters of Science. Department of
Natural Resource Sciences, McGill University, Montreal, Canada.
79. Crump, D., Egloff, C., Chiu, S., et al. 2010. Pipping success,
isomer-specific accumulation, and hepatic mRNA expression in chicken
embryos exposed to HBCD. Toxicol. Sci. 115:492-500.
80. Wu, T., Wang, S., Huang, H., et al. 2012. Diastereomer-specific
uptake, translocation, and toxicity of hexabromocyclododecane
diastereoisomers to maize. J. Agr. Food Chem. 60:8528-8534.
81. Drottar, K.R. and Krueger, H.O. 2000. Hexabromocyclododecane
(HBCD): A flow-through bioconcentration test with the rainbow trout
(Oncorhynchus mykiss). Report# 439A-111. Wildlife International Ltd,
Easton, MD, pp 1-137. Submitted under TSCA Section FYI; EPA Document
No.<PHONE_NUMBER>1; OTS0001392.
82. Veith, G.D., Defoe, D.L., Bergstedt, B.V. 1979. Measuring and
estimating the bioconcentration factor of chemicals in fish. J. Fish
Res. Board Can. 36:1040-1048.
83. Zhang, Y., Sun, H., Ruan, Y. 2014. Enantiomer-specific
accumulation, depuration, metabolization and isomerization of
hexabromocyclododecane (HBCD) diastereomers in mirror carp from
water. J. Haz. Mater. 264:8-15.
84. He, M., Luo, X., Yu, L., et al. 2013. Diasteroisomer and
enantiomer-specific profiles of hexabromocyclododecane and
tetrabromobisphenol A in an aquatic environment in a highly
industrialized area, South China: Vertical profile, phase partition,
and bioaccumulation. Environ. Poll. 179:105-110.
85. Wu, J., Guan, Y., Zhang, Y., et al. 2011. Several current-use,
non-PBDE brominated flame retardants are highly bioaccumulative:
Evidence from field determined bioaccumulation factors. Environ.
Int. 37:210-215.
86. La Guardia, M.J., Hale, R.C., Harvey, E., et al. 2012. In situ
accumulation of HBCD, PBDEs, and several alternative flame-
retardants in the bivalve (Corbicula fluminea) and gastropod (Elimia
proxima). Environ. Sci. Technol. 46:5798-5805.
87. Law, K., Palace, V.P., Halldorson, T., et al. 2006. Dietary
accumulation of hexabromocyclododecane diastereoisomers in juvenile
rainbow trout (Oncorhynchus mykiss) I: Bioaccumulation parameters
and evidence of bioisomerization. Environ. Toxicol. Chem.
25(7):1757-1761.
88. Esslinger, S., Becker, R., M[uuml]ller-Belecke, A., et al. 2010.
HBCD stereoisomer pattern in mirror carps following dietary exposure
to pure [gamma]-HBCD enantiomers. J. Agric. Food Chem. 58:9705-9710.
89. Du, M., Lin, L., Yan, C., et al. 2012. Diastereoisomer- and
enantiomer-specific accumulation, depuration, and bioisomerization
of hexabromocyclododecanes in zebrafish (Danio rerio). Environ. Sci.
Technol. 46:11040-11046.
90. Marvin, C.H., Tomy, G.T., Armitage, J.M., et al. 2011.
Hexabromocyclododecane: Current understanding of chemistry,
environmental fate and toxicology and implications for global
management. Environ. Sci. Technol. 45:8613-8623. Including
supporting information document.
91. Zhang, Y., Sun, H., Zhu, H., et al. 2014. Accumulation of
hexabromocyclododecane diastereomers and enantiomers in two
microalgae, Spirulina subsalsa and Scenedesmus obliquus. Ecotox.
Environ. Safe. 104:136-142.
92. Harrad, S; Abdallah, MA; Covaci, A. (2009a) Causes of
variability in concentrations and diastereomer patterns of
Hexabromocyclododecanes in indoor dust. Environment International
35:573-579.
93. USEPA. 2011. EPI Suite results for CAS 003194-55-6. Download EPI
SuiteTM v4.0. U.S. Environmental Protection Agency. Available online
at http://www.epa.gov/opptintr/exposure/pubs/episuitedl.htm (see
section 2, attachment A in Ref. 1).
94. Schaefer, E.C. and Haberlein, D. 1996. Hexabromocyclododecane
(HBCD): Closed bottle test. 439E-102, Wildlife International Ltd,
Easton, MD, USA (as cited in Ref. 44).
95. Davis, J.W., Gonsior, S.J., Markham, D.A., et al. 2006.
Biodegradation and product identification of
[\14\C]hexabromocyclododecane in wastewater sludge and freshwater
aquatic sediment. Environ. Sci. Technol. 40:5395-5401. Including
supporting information document.
96. Davis, J.W., Gonsior, S.J., Marty, G.T., et al. 2005. The
transformation of hexabromocyclododecane in aerobic and anaerobic
soils and aquatic sediments. Water Res. 39:1075-1084.
97. Hazardous Substance Data Bank. 2011. 1,2,5,6,9,10-
Hexabromocyclododecane. Hazardous Substances Data Bank. Part of the
National Library of Medicine's Toxicology Data Network (TOXNET7).
Bethesda, MD. Available online at http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?HSDB (accessed May 31, 2011).
98. Bidleman, T.F. 1988. Atmospheric processes. Environ. Sci.
Technol. 22(4):361-367.
99. Stenzel, J.I., Nixon, W.B. 1997. Hexabromocyclododecane (HBCD):
Determination of the vapor pressure using a spinning rotor gauge
with cover letter dated 08/15/1997. Chemical Manufacturers
Association. Submitted under TSCA Section 8D. OTS0573702.
100. USEPA. 1993. Determination of rates of reaction in the gas-
phase in the troposphere. 5. Rate of indirect photoreaction:
Evaluation of the atmospheric oxidation computer program of Syracuse
Research Corporation for estimating the second-order rate constant
for the reaction of an organic chemical with hydroxyl radicals.
Washington, DC: U.S. Environmental Protection Agency. EPA744R93001.
101. National Industrial Chemicals Notification and Assessment
Scheme. 2012. Hexabromocyclododecane. Priority existing chemical
assessment report. Volume 34. Commonwealth of Australia: Australia.
National Industrial Chemicals Notification and Assessment Scheme.
PEC34.
102. Davis, J.W., Gonsior, S.J., Marty, G.T. 2003. Evaluation of
aerobic and anaerobic transformation of hexabromocyclododecane in
aquatic sediment systems. Project Study ID 021081, 87 pp. DOW
Chemical Company: Midland, MI, USA. Submitted under TSCA Section
FYI; EPA Document No.<PHONE_NUMBER>0; FYI-1103-01472, pg. 440.
103. Davis, J.W., Gonsior, S.J., Marty, G.T. 2003. Evaluation of
aerobic and anaerobic transformation of hexabromocyclododecane in
soil. Project Study ID 021082, 61 pp. DOW Chemical Company: Midland,
MI, USA. Submitted under TSCA Section FYI; EPA Document No.
84040000010; FYI-1103-01472, pg. 379.
104. USEPA. 2010. Hexabromocyclododecane (HBCD) action plan. U.S.
Environmental Protection Agency. August 18, 2010.

VI. What are the Statutory and Executive Orders reviews associated with
this action?

    Additional information about these statutes and Executive Orders
can be found at http://www2.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review

    This action is not a significant regulatory action and was
therefore not submitted to the Office of Management and Budget (OMB)
for review under Executive Orders 12866 (58 FR 51735, October 4, 1993)
and 13563 (76 FR 3821, January 21, 2011).

B. Paperwork Reduction Act (PRA)

    This action does not contain any new information collection
requirements that require additional approval by OMB under the PRA, 44
U.S.C. 3501 et seq. OMB has previously approved the information
collection activities contained in the existing regulations and has
assigned OMB control numbers 2025-0009 and 2050-0078. Currently, the
facilities subject to the reporting requirements under EPCRA section
313 and PPA section 6607 may use either EPA Toxic Chemicals Release
Inventory Form R (EPA Form 1B9350-1), or EPA Toxic Chemicals Release
Inventory Form A (EPA Form 1B9350- 2). The Form R must be completed if
a facility manufactures, processes, or otherwise uses any listed
chemical above threshold quantities and meets certain other criteria.
For the Form A, EPA established an alternative threshold for facilities
with low annual reportable amounts of a listed toxic chemical. A
facility that meets the appropriate reporting thresholds, but estimates
that the total annual reportable amount of the chemical does not exceed
500 pounds per year, can take advantage of an alternative manufacture,
process, or otherwise use threshold of 1 million pounds per year of the
chemical, provided that certain conditions are met, and submit the Form
A instead of the Form R. Since the HBCD category would be classified a
PBT category, it is designated as a chemical of special concern, for
which Form A reporting is not allowed. In addition, respondents may
designate the specific chemical identity of a substance as a trade
secret pursuant to EPCRA section 322, 42 U.S.C. 11042, 40 CFR part 350.
    OMB has approved the reporting and recordkeeping requirements
related to Forms A and R, supplier notification, and petitions under
OMB Control number 2025-0009 (EPA Information Collection Request (ICR)
No. 1363) and those related to trade secret designations under OMB
Control 2050-0078 (EPA ICR No. 1428). As provided in 5 CFR 1320.5(b)
and 1320.6(a), an Agency may not conduct or sponsor, and a person is
not required to respond to, a collection of information unless it
displays a currently valid OMB control number. The OMB control numbers
relevant to EPA's regulations are listed in 40 CFR part 9 or 48 CFR
chapter 15, and displayed on the information collection instruments
(e.g., forms, instructions).

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA, 5
U.S.C. 601 et seq. The small entities subject to the requirements of
this action are small manufacturing facilities. The Agency has
determined that of the 55 entities estimated to be impacted by this
action, 42 are small businesses; no small governments or small
organizations are expected to be affected by this action. All 42 small
businesses affected by this action are estimated to incur annualized
cost impacts of less than 1%. Thus, this action is not expected to have
a significant adverse economic impact on a substantial number of small
entities. A more detailed analysis of the impacts on small entities is
located in EPA's economic analysis (Ref. 2).

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or
more as described in UMRA, 2 U.S.C. 1531-1538, and does not
significantly or uniquely affect small governments. This action is not
subject to the requirements of UMRA because it contains no regulatory
requirements that might significantly or uniquely affect small
governments. Small governments are not subject to the EPCRA section 313
reporting requirements. EPA's economic analysis indicates that the
total cost of this action is estimated to be $372,973 in the first year
of reporting (Ref. 2).

E. Executive Order 13132: Federalism

    This action does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999). It will not have
substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

    This action does not have tribal implications as specified in
Executive Order 13175 (65 FR 67249, November 9, 2000). This action
relates to toxic chemical reporting under EPCRA section 313, which
primarily affects private sector facilities. Thus, Executive Order
13175 does not apply to this action.

G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks

    EPA interprets Executive Order 13045 (62 FR 19885, April 23, 1997)
as applying only to those regulatory actions that concern environmental
health or safety risks that EPA has reason to believe may
disproportionately affect children, per the definition of ``covered
regulatory action'' in section 2-202 of the Executive Order. This
action is not subject to Executive Order 13045 because it does not
concern an environmental health risk or safety risk.

H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use

    This action is not subject to Executive Order 13211 (66 FR 28355,
May 22, 2001), because it is not a significant regulatory action under
Executive Order 12866.

I. National Technology Transfer and Advancement Act (NTTAA)

    This rulemaking does not involve technical standards and is
therefore not subject to considerations under section 12(d) of NTTAA,
15 U.S.C. 272 note.

J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations

    EPA has determined that this action will not have
disproportionately high and adverse human health or environmental
effects on minority or low-income populations as specified in Executive
Order 12898 (59 FR 7629, February 16, 1994). This action does not
address any human health or environmental risks and does not affect the
level of protection provided to human health or the environment. This
action adds an additional chemical to the EPCRA section 313 reporting
requirements. By adding a chemical to the list of toxic chemicals
subject to reporting under section 313 of EPCRA, EPA would be providing
communities across the United States (including minority populations
and low income populations) with access to data which they may use to
seek lower exposures and consequently reductions in chemical risks for
themselves and their children. This information can also be used by
government agencies and others to identify potential problems, set
priorities, and take appropriate steps to

reduce any potential risks to human health and the environment.
Therefore, the informational benefits of the action will have positive
human health and environmental impacts on minority populations, low-
income populations, and children.

List of Subjects in 40 CFR Part 372

    Environmental protection, Community right-to-know, Reporting and
recordkeeping requirements, and Toxic chemicals.

    Dated: May 16, 2016.
Gina McCarthy,
Administrator.
    Therefore, it is proposed that 40 CFR chapter I be amended as
follows:

PART 372--[AMENDED]

0
1. The authority citation for part 372 continues to read as follows:

    Authority:  42 U.S.C. 11023 and 11048.

0
2. In Sec.  372.28, amend the table in paragraph (a)(2) as follows:
0
a. Revise the heading for the second column, and
0
b. Alphabetically add the category ``Hexabromocyclododecane (This
category includes only those chemicals covered by the CAS numbers
listed here)'' and list ``3194-55-6 (1,2,5,6,9,10-
Hexabromocyclododecane)'' and ``25637-99-4 (Hexabromocyclododecane)''
    The additions to read as follows:

Sec.  372.28  Lower thresholds for chemicals of special concern.

    (a) * * *
    (2) * * *

------------------------------------------------------------------------
                                                            Reporting
                                                          threshold (in
                     Category name                        pounds unless
                                                        otherwise noted)
------------------------------------------------------------------------

                              * * * * * * *
Hexabromocyclododecane (This category includes only                  100
 those chemicals covered by the CAS numbers listed
 here)................................................
 3194-55-6 1,2,5,6,9,10-Hexabromocyclododecane........  ................
25637-99-4 Hexabromocyclododecane.....................  ................

                              * * * * * * *
------------------------------------------------------------------------

* * * * *
0
3. In Sec.  372.65, paragraph (c) is amended by adding alphabetically
an entry for ``Hexabromocyclododecane (This category includes only
those chemicals covered by the CAS numbers listed here)'' to the table
to read as follows:

Sec.  372.65  Chemicals and chemical categories to which this part
applies.

* * * * *
    (c) * * *

------------------------------------------------------------------------
                     Category name                       Effective date
------------------------------------------------------------------------

                              * * * * * * *
Hexabromocyclododecane (This category includes only               1/1/17
 those chemicals covered by the CAS numbers listed
 here)................................................
 3194-55-6 1,2,5,6,9,10-Hexabromocyclododecane........  ................
25637-99-4 Hexabromocyclododecane.....................  ................

                              * * * * * * *
------------------------------------------------------------------------

[FR Doc. 2016-12464 Filed 6-1-16; 8:45 am]
 BILLING CODE 6560-50-P