TSCA Work Plan Chemical 

Technical Supplement – Hazard Assessment of the Brominated 

Phthalates Cluster (BPC) Chemicals 

Brominated Phthalates Cluster 

Flame Retardants 

CASRN NAME 

26040-51-7 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1,2-bis(2-

ethylhexyl) ester 

183658-27-7 Benzoic acid, 2,3,4,5-tetrabromo-, 2-ethylhexyl ester 

20566-35-2 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1-[2-(2-

hydroxyethoxy)ethyl] 2-(2-hydroxypropyl) ester 

77098-07-8 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, mixed 

esters with diethylene glycol and propylene glycol 

7415-86-3 1,2-Benzenedicarboxylic acid, 1,2-bis(2,3-dibromopropyl) ester 

* Confidential A 

* Confidential B 

* Confidential Business Information 

August 2015 

United States 

Environmental Protection Agency

EPA Document# 740-Q1-4003 

August 2015 

Office of Chemical Safety and 

Pollution Prevention
Page 2 of 23 

TABLE OF CONTENTS 

TABLE OF CONTENTS ............................................................................................................. 2

1 HUMAN HEALTH HAZARD ............................................................................................... 3

TOXICOKINETICS ................................................................................................................................................ 3

HAZARD IDENTIFICATION .................................................................................................................................... 8

DATA NEEDS ASSESSMENT ................................................................................................................................ 16

2 ECOLOGICAL HAZARD ................................................................................................... 17

HAZARD IDENTIFICATION .................................................................................................................................. 17

DATA NEEDS ASSESSMENT ................................................................................................................................ 19

REFERENCES ........................................................................................................................ 21

LIST OF TABLES 

Table 1-1: Structure of Brominated Phthalates Cluster and Associated Chemicals ....................... 5

Table 1-2: Availability of human health data for the Brominated Phthalates Cluster ................... 8

Table 1-3: Human Health Data for Brominated Phthalates Cluster ............................................. 10

Table 2-1: Environmental Effects Data for Brominated Phthalates Cluster ................................. 18
Page 3 of 23 

1 HUMAN HEALTH HAZARD 

Toxicokinetics 

Limited data are available on the toxicokinetics of the BPC members. Phthalic acid is the 

common final metabolite of phthalic acid esters in rats; the main route of excretion being in 

urine (Lim et al., 2007). While information for the structural analogue, bis(2-

ethylhexyl)phthalate (DEHP; CASRN 117-81-7) can be used to inform the metabolism and 

potential hazard of some of the BPC members, it is not appropriate for all members due to the 

differences in metabolites. The metabolites of DEHP and the cluster members are depicted in 

Table 1-1. 

1,2-Benzenedicarboxylic acid, 1,2-bis(2-ethylhexyl) ester (DEHP; CASRN 117-81-7) 

The closest structural analog of the cluster members is 1,2-Benzenedicarboxylic acid, 1,2-bis(2-

ethylhexyl) ester (DEHP; CASRN 117-81-7). It is readily absorbed and distributed in the body. Its 

metabolism involves several pathways and yields a variety of metabolites; more than 30 

metabolites have been identified (Lim et al., 2007). The major step in the metabolism of DEHP 

is hydrolysis by lipases to mono (2-ethylhexyl)phthalate (MEHP; CASRN 4376-20-9) and 2-

ethylhexanol (2-EH; CASRN 104-76-7). Phthalic acid (PA; CASRN 88-99-3) is the common final 

metabolite of phthalic acid esters (Lim et al., 2007). DEHP is excreted via the urine, mainly as

MEHP-metabolites, but some excretion via bile also occurs in rodents. Additionally, there are 

animal and human data showing that DEHP is transferred to mothers’ milk. The relative extent 

to which different metabolites are produced and excreted is very complex and may depend 

upon the species, the age of the animal, sex, inter-individual differences, nutrition state, prior 

exposure to DEHP, the amount of DEHP administered, and the route of administration (NTP, 

2006; OECD, 2005). 

1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1,2-bis(2-ethylhexyl) ester (TBPH; CASRN 

26040-51-7) 

Limited data are available on the toxicokinetics of 1,2-Benzenedicarboxylic acid, 3,4,5,6-

tetrabromo-, 1,2-bis(2-ethylhexyl) ester (TBPH; CASRN 26040-51-7). Its primary metabolite is 

the monoester, mono(2-ethylhexyl) tetrabromophthalate (TBMEHP; CASRN 61776-60-1) which 

is then ultimately metabolized to tetrabromophthalic acid (CASRN 13810-83-8). When tested in 

vitro, no metabolites of TBPH were detected in human or rat subcellular fractions (Roberts et 

al., 2012). However, in the presence of purified porcine carboxylesterase, the formation of 

TBMEHP was detected. No phase II metabolites of TBMEHP were detected. The metabolism of 

TBPH in humans has not been evaluated (Roberts et al., 2012). No toxicokinetics data were 

submitted to EPA under the HPV Challenge Program (ACC, 2004) and additional information 

was not publicly available from the European Chemicals Agency (ECHA) site (ECHA, 2013). 

Benzoic acid, 2,3,4,5-tetrabromo-, 2-ethylhexyl ester (TBB; CASRN 183658-27-7) 

Limited data are available on the toxicokinetics of Benzoic acid, 2,3,4,5-tetrabromo-, 2-

ethylhexyl ester (TBB; CASRN 183658-27-7). This member of the cluster differs significantly 
Page 4 of 23 

from the other cluster members in that its final metabolite is not tetrabromophthalic acid 

(CASRN 13810-83-8) but tetrabromobenzoic acid (TBBA; CASRN 27581-13-1). This was 

confirmed in vitro using liver and intestinal subcellular fractions. In all experiments, TBB was 

consistently metabolized to 2,3,4,5-tetrabromobenzoic acid (TBBA) via cleavage of the 2-

ethylhexyl chain without requiring added cofactors (Roberts et al., 2012). No phase II 

metabolites of TBBA were detected. The metabolism of TBB in humans has not been evaluated 

(Roberts et al., 2012). 

1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1-[2-(2-hydroxyethoxy)ethyl] 2-(2-

hydroxypropyl) ester (CASRN 20566-35-2) and 3,4,5,6 tetrabromo-1,2-benzene dicarboxylic 

acid, mixed esters with diethylene glycol and propylene glycol (CASRN 77098-07-8) 

These two cluster members are mixtures which can be considered together as their 

composition and metabolites are very similar. No data on the toxicokinetics of these substances 

are available. Analogous to the other cluster members, the metabolites are expected to be the 

corresponding alcohols and the tetrabromophthalic acid. No toxicokinetics data were 

submitted for CASRN 77098-07-8 to EPA under the HPV Challenge Program (Albemarle - GLCC, 

2004) and additional information was not publicly available from the European Chemicals 

Agency (ECHA) site for CASRN 20566-35-2 (ECHA, 2013). 

1,2-Benzenedicarboxylic acid, 1,2-bis(2,3-dibromopropyl) ester (CASRN 7415-86-3) 

No data are available on the toxicokinetics of this cluster member. It differs from the other 

cluster members in that the bromines are not attached to the benzene ring but are instead on 

the side-chains. The metabolites are expected to be 2,3-dibromopropanol (CASRN 96-13-9) and 

the final metabolite, PA. Two mercapturic acid metabolites of 2,3-dibromopropanol have been 

identified in the urine of treated rats (IARC, 2000). 
Page 5 of 23 

Table 1-1: Structure of Brominated Phthalates Cluster and Associated Chemicals 

CASRN NAME STRUCTURE Metabolites/Hydrolysis Pro

117-81-7 DEHP: ,2-

Benzenedicarboxylic acid, ,2-bis(2-ethylhexyl)ester STRUCTURAL ANALOG of BPC CLUSTER MEMBERS MEHP 

[Mono(2-ethylhexyl) 

tetrabromophthalate; 

CASRN 4376-20-9]1

2-ethy

(CASRN 

Phtha

(CASRN 

26040-51-7 TBPH: 1,2-

Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1,2-bis(2-ethylhexyl) ester

TBMEHP 

[Mono(2-ethylhexyl) 

tetrabromophthalate; 

CASRN 61776-60-1; not 

on TSCA inventory] 

2-ethy

(CASRN 

Tetrabromo

(CASRN 1

1 CSID:19208, http://www.chemspider.com/Chemical-Structure.19208.html (accessed 15:06, Sep 9, 2013) 

B

BrBr

B
Page 6 of 23 

CASRN NAME STRUCTURE Metabolites/Hydrolysis Pro

183658-27-7 TBB: Benzoic acid, 

2,3,4,5-tetrabromo-, 2-ethylhexyl ester

2-ethylhexanol 

(CASRN 104-76-7)

20566-35-2 TBPA-Diol: 1,2-

Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1-[2-(2-hydroxyethoxy)ethyl] 2-(2-hydroxypropyl) ester

HOCH2CH2OCH2C

H2OH 

Diethylene glycol

(CASRN 111-46-6)

 CH3-CHOHCH2OH

Propylene Glycol

(CASRN 57-55-6)

77098-07-8 TBPA-Diol (Mixed 

Esters): 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, mixed esters with diethylene glycol and propylene glycol

HOCH2CH2OCH2C

H2OH 

Diethylene glycol

(CASRN 111-46-6)

CH3-CHOHCH2OH

Propylene Glycol

(CASRN 57-55-6) 
Page 7 of 23 

CASRN NAME STRUCTURE Metabolites/Hydrolysis Pro

7415-86-3 Bromo Alkyl Ester: 

1,2-Benzenedicarboxylic acid, 1,2-bis(2,3-dibromopropyl) ester

2,3-dibromo-1-

propanol

(CASRN 96-13-9) 

CONFIDENTIAL A

CONFIDENTIAL B
Page 8 of 23 

Hazard Identification 

The available hazard data for the BPC cluster members are summarized in Table 1-3 and Table 2-1. Table 1-3 als

hazard data for the structural analog, DEHP, for reference. The data are discussed below. 

Table 1-2: Availability of human health data for the Brominated Phthalates Cluster 

Brominated Phthalates Cluster Members 

Endpoint CASRN 

26040-51-72

CASRN 

183658-27-73

CASRN 

20566-35-24

CASRN 

77098-07-85

CASRN 

7415-86-3 

Confident

A 

 TBPH: 1,2-

Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1,2-bis(2-ethylhexyl) ester

TBB: Benzoic acid, 2,3,4,5-tetrabromo-, 2-ethylhexyl ester

TBPA-Diol: 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1-[2-(2-hydroxyethoxy)ethyl] 2-(2-hydroxypropyl) ester

TBPA-Diol: 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, mixed esters with diethylene glycol and propylene glycol

1,2-Benzenedicarboxylic acid, 1,2-bis(2,3-dibromopropyl) ester

Acute Oral Toxicity LD50 (mg/kg) 

X — ECHA X — — 

Acute Dermal Toxicity LD50

(mg/kg) 

X — ECHA X — — 

2 Screening-level data available from the HPV Challenge submission: http://www.epa.gov/hpv/pubs/summaries/phthacid/c15484tc.htm3 Data available for Firemaster BZ 54 (TBB/TBPH mixture) 4 Screening-level data are available from ECHA [(European Chemicals Agency): http://apps.echa.europa.eu/registered/data/dossiers/DIe044-00144f67d031/DISS-9ea569d1-072b-18ab-e044-00144f67d031_DISS-9ea569d1-072b-18ab-e044-00144f67d031.html] For risk aof these data is indeterminable without access to the full studies. 5 Screening-level data available from the HPV Challenge submission: http://www.epa.gov/chemrtk/pubs/summaries/12benznd/c15091t
Page 9 of 23 

Brominated Phthalates Cluster Members 

Endpoint CASRN 

26040-51-72

CASRN 

183658-27-73

CASRN 

20566-35-24

CASRN 

77098-07-85

CASRN 

7415-86-3 

Confident

A 

Acute Inhalation Toxicity LC50 (mg/L) — — — X — — Repeated-Dose Toxicity Oral NOAEL/ LOAEL (mg/kg-day)

X — — — — — 

Reproductive Toxicity NOAEL/ LOAEL (mg/kg-day) — — — — — — Developmental Toxicity NOAEL/ LOAEL (mg/kg-day) — — — — — — Genetic Toxicity – Gene Mutation In vitro

X — ECHA X — — 

Genetic Toxicity – Chromosomal Aberrations In vitro

X — — — — — 

Genetic Toxicity – Chromosomal Aberrations In vivo

X — — — — — 

Skin Irritation X — — — — — 
Page 10 of 23 

Brominated Phthalates Cluster Members 

Endpoint CASRN 

26040-51-72

CASRN 

183658-27-73

CASRN 

20566-35-24

CASRN 

77098-07-85

CASRN 

7415-86-3 

Confident

A 

Eye Irritation X — — — — — Sensitization X — — — — — 

 X denotes available data; - denotes no adequate data Table 1-3: Human Health Data for Brominated Phthalates Cluster

Brominated Phthalates Cluster Members

Endpoint CASRN 

117-81-76

CASRN 

26040-51-77

CASRN 

183658-27-7 

CASRN 

20566-35-28

CASRN 

77098-07-89

DEHP: 1,2-Benzendicarboxylic acid, 2-bis(2-ethylhexyl ester) 

TBPH: 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1,2-bis(2-ethylhexyl) ester

TBB: Benzoic acid, 2,3,4,5-tetrabromo-, 2-ethylhexyl ester

TBPA-Diol: 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1-[2-(2-hydroxyethoxy)ethyl] 2-(2-hydroxypropyl) ester

TBPA-Diol: 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, mixed esters with diethylenglycol and propylene glycol

Acute Oral ToxicityLD50 (mg/kg) 

>20,000 >5000 

(>95%) — >2000 (Saytex RB 79 

20566-35-2)

>10,000 

(PM-PHT-4 Diol)

(Firemaster® BZ-54)10

>5000 

6 ECHA: http://apps.echa.europa.eu/registered/data/dossiers/DISS-9c7eba3b-31b2-3fd1-e044-00144f67d249/DISS-9c7eba3b-31b2-300144f67d249_DISS-9c7eba3b-31b2-3fd1-e044-00144f67d249.html7 HPV Challenge submission: http://www.epa.gov/hpv/pubs/summaries/phthacid/c15484tc.htm8 ECHA: http://apps.echa.europa.eu/registered/data/dossiers/DISS-9ea569d1-072b-18ab-e044-00144f67d031/DISS-9ea569d1-072b-100144f67d031_DISS-9ea569d1-072b-18ab-e044-00144f67d031.html For risk assessment, the adequacy of these data is indeterminabfull studies. 9 Screening-level data available from the HPV Challenge submission: http://www.epa.gov/chemrtk/pubs/summaries/12benznd/c150910 (NICNAS, 2004) 
Page 11 of 23 

Brominated Phthalates Cluster Members

Endpoint CASRN 

117-81-76

CASRN 

26040-51-77

CASRN 

183658-27-7 

CASRN 

20566-35-28

CASRN 

77098-07-89

Acute Dermal Toxicity LD50

(mg/kg)

19,800 >3090 

(>95%) — >20,000 (FM-PHT-4 Diol 

20566-35-2)

>20,000 

(PM-PHT-4 Diol) 

(Firemaster® BZ-54)14

>2000 

Acute Inhalation Toxicity LC50 (mg/L)

10,620 [LC0] 

(mg/m3) 

— — >0.008 

(FM-PHT-4 Diol 

20566-35-2) 

— 

Repeated-Dose ToxicityOral NOAEL/LOAEL(mg/kg-day)

(rat; diet chronic) 

NOAEL=29-36 

LOAEL 

=146-181 

(rat; 28-d diet) 

NOAEL =223 

(2000 ppm) 

LOAEL = 2331 

(20,000 ppm) 

(>95%) — — — 

(Firemaster® BZ-54)14

Rat (28-d gavage) 

NOEL = Not established 

LOEL = 160 

Repeated-Dose ToxicityInhalationNOAEC/LOAEC(mg/L-day)

NOAEC= 

50 mg/m3 

LOAEC= 

1000 mg/m3 — — — — 

Reproductive ToxicityOralNOAEL/LOAEL(mg/kg-day) 

(Rat; 3-gen) 

NOAEL=46-48 

LOAEL=359-391 

(parental) 

NOAEL(offspring)=1.4 

LOAEL(offspring)=4.8-4.9 

(Rat; 2-gen) 

NOAEL=165 (highest dose tested) 

NOAEL(parental) = 50 

LOAEL(parental) = 

165 

NOAEL(off-spring)=50 

LOAEL(off-spring)=165 

(Firemaster® BZ-54)14 

— — 
Page 12 of 23 

Brominated Phthalates Cluster Members

Endpoint CASRN 

117-81-76

CASRN 

26040-51-77

CASRN 

183658-27-7 

CASRN 

20566-35-28

CASRN 

77098-07-89

Developmental ToxicityNOAEL/LOAEL(mg/kg-day)

Maternal 

Toxicity 

Developmental 

Toxicity

(Rat) 

NOAEL = 200 

LOAEL =1000 

NOAEL=200 

LOAEL=1000 

(Rat) 

NOAEL = 50 

LOAEL =100 

NOAEL=50 

LOAEL=100 

(Firemaster® BZ-54)14 — — 

Genetic Toxicity –Gene MutationIn vitro

— Negative 

(>95%) — Negative (Saytex RB 79 

20566-35-2)

Negative 

(Saytex RB 79) 

Genetic Toxicity –Chromosomal AberrationsIn vitro

Negative 

(SCE) 

Positive 

(>95%) — — — 

Genetic Toxicity –Chromosomal AberrationsIn vivo

Negative Negative 

(>95%) — — — 

Skin Irritation Slightly irritating Slightly irritating 

(>95%) — — — 

Eye Irritation — Slightly irritating 

(>95%) — — — 

Sensitization Not sensitizing 

(skin or 

respiratory) 

Not sensitizing 

(>95%) — — — 

Carcinogenicity Positive 

(rat) — — — — 

Measured data in bold; NE = Not established; — indicates no data or no reliable data for this endpoint; (%) = % purity or iden

test substance
Page 13 of 23 

1,2-Benzenedicarboxylic acid, 1,2-bis(2-ethylhexyl) ester (DEHP; CASRN 117-81-7) 

Several assessments are available on the toxicity and risks of phthalates. EPA has published a 

screening-level hazard characterization for phthalate esters (EPA, 2010a) and has revised the 

action plan for phthalates (EPA, 2012d); both of which use data for bis(2-ethylhexyl)phthalate 

(DEHP; CASRN 117-81-7) to ascribe hazard. DEHP is metabolized by esterases to mono (2-

ethylhexyl)phthalate (MEHP; CASRN 4376-20-9), its toxicologically active monoester (Springer 

et al., 2012). DEHP is a known peroxisome proliferator and male reproductive toxicant in 

rodents. It induces hepatotoxicity in rodents, most likely as a result of MEHP-induce activation 

of peroxisome proliferator activated receptor alpha (PPARα) (Ward et al., 1998 cited in Springer 

et al., 2012). The developing male reproductive system in rats is highly sensitive to the effects 

of these phthalates, which decrease fetal male testosterone levels (Parks et al., 2000 cited in 

Springer et al., 2012). In 2006, the National Toxicology Program (NTP) deliberated on the 

reproductive toxicity of DEHP and concluded the following: there is serious concern that 

certain intensive medical treatments of male infants may result in DEHP exposure levels that 

adversely affect development of the male reproductive tract, there is concern for adverse 

effects on development of the reproductive tract in male offspring of pregnant and 

breastfeeding women undergoing certain medical procedures involving high DEHP exposures, 

there is concern for the effects of DEHP exposure on the development of the male reproductive 

tract for infants less than one year old and less so for male children older than one year old and 

there is concern for adverse effects of DEHP exposure on development of the male 

reproductive tract in male offspring of pregnant women not medically exposed to DEHP and 

some concern for reproductive toxicity in adults exposed to DEHP at 1-30 μg/kg bw/day (NTP, 

2006). It is this toxicity to the male reproductive system from DEHP exposure, a phthalate ester, 

that is of specific concern for this cluster of brominated phthalate esters. 

1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1,2-bis(2-ethylhexyl) ester (TBPH; CASRN 

26040-51-7) 

bis(2-Ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH) exhibits low acute toxicity to rats and 

rabbits via the oral and dermal routes, respectively. It is slightly irritating to the skin and eyes in 

rabbits and was not a skin sensitizer in guinea pigs. In a dietary repeat-dose study in rats, there 

was a slight body weight decrease in females and clinical biochemistry perturbations 

(decreased alanine aminotransferase activity, decreased calcium and decreased phosphorus 

levels) at the highest concentration tested (2331 mg/kg-day). The NOAEL was designated as 223 

mg/kg-day. TBPH was not mutagenic in bacteria in vitro but did induce chromosomal 

aberrations in mammalian cells in vitro. TBPH did not induce micronuclei in mice in vivo. No 

data are available for the reproductive/developmental toxicity endpoint. 

In a non-guideline study, Springer et al., (2012) compared the toxicity of the primary metabolite 

of TBPH [mono(2-ethylhexyl) tetrabromophthalate (TBMEHP; CASRN 61776-60-1)] with that of 

DEHP [mono (2-ethylhexyl)phthalate (MEHP; CASRN 4376-20-9)]. Dust collected from homes, 

offices, and cars was measured for TBPH by gas chromatography followed by mass 

spectrometry. Pregnant rats were gavaged with TBMEHP (200 or 500 mg/kg) or corn oil on 

gestational days 18 and 19, and dams and fetuses were evaluated histologically for toxicity. 

TBMEHP was also evaluated for deiodinase inhibition using rat liver microsomes and for 
Page 14 of 23 

peroxisome proliferator-activated receptor (PPAR) α and γ activation using murine FAO cells 

and NIH 3T3 L1 cells. They found that in contrast to DEHP, TBMEHP did not exhibit antiandrogenic activity. However, it did exhibit liver toxicity attributable to a PPAR α mode of action 

which is similar to that observed for DEHP/MEHP. 

Benzoic acid, 2,3,4,5-tetrabromo-, 2-ethylhexyl ester (TBB; CASRN 183658-27-7) 

Limited toxicity data are available for Benzoic acid, 2,3,4,5-tetrabromo-, 2-ethylhexyl ester 

(TBB; CASRN 183658-27-7). The available data (Chemtura, 2012a, 2013a; NICNAS, 2004) are for 

the commercial product, Firemaster® BZ-54. This commercial product is a mixture of TBB and 2-

ethylhexyl tetrabromophthalate (TBPH; CASRN 26040-51-7) (Chemtura, 2010). Firemaster® BZ54 exhibits low acute toxicity via the oral and dermal routes of exposure. In a 28-day repeated 

dose study in rats, kidney effects (cortical tubular epithelial regeneration) and increased levels 

of mean serum chloride were observed at all dose levels. The females appeared more sensitive 

to the test substance (significant differences in organ weights, changes in clinical chemistry 

parameters, decreased in mean body weight gain); the no observed adverse effect level was 

not determined. The lowest observed effect level was 160 mg/kg-day. The effects observed in 

parental animals in the two-generation reproductive toxicity study with Firemaster® BZ-54 were 

lower body weights and body weight gains during the premating periods in the parental and 

first generation females at the highest dose tested. First generation males also had lower body 

weights in the premating period but body weight gain was unaffected by treatment. At the 

highest dose tested, both generations of offspring had lower body weights at birth and 

throughout lactation which resulted in the lower premating body weights of the first female 

generation. Another effect of treatment was lower spleen weights at lactation day 21 in the 

first generation male pups and both pup sexes of the second generation. There were no 

adverse effects on reproductive performance or fertility in rats in this study up to the highest 

dose tested (165 mg/kg-day). Based on these observations, the NOAEL for parental and 

neonatal toxicity was designated 50 mg/kg-day; the NOAEL for reproductive toxicity was 165 

mg/kg-day (highest dose tested). 

In the prenatal developmental toxicity study with Firemaster®BZ-54 in rats, maternal toxicity 

included clinical findings (increased incidence of animals with sparse hair in the abdominal 

region), lower gestation body weights and body weight gain, and lower gestation food 

consumption at doses greater than or equal to 100 mg/kg-day. Fetal body weights were lower 

than controls at these doses. At 300 mg/kg-day, examination of the fetuses indicated fused 

cervical vertebral neural arches which were considered treatment-related (litter incidence of 

8%). In addition, there was also an increased litter incidence for fetal ossification variations 

involving additional ossification centers to the cervical vertebral neural arches, incomplete 

ossified skull bones (jugal, parietal, and squamosal), and unossified sternebrae. Based on these 

observations, the NOAEL for maternal and developmental toxicity were designated 50 mg/kgday. 
Page 15 of 23 

1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1-[2-(2-hydroxyethoxy)ethyl] 2-(2-

hydroxypropyl) ester (CASRN 20566-35-2) and 3,4,5,6 tetrabromo-1,2-benzene dicarboxylic 

acid, mixed esters with diethylene glycol and propylene glycol (CASRN 77098-07-8) 

CASRNs 20566 and 77098-07-8 exhibit low acute toxicity to rats and rabbits via the oral and 

dermal routes, respectively. They are not mutagenic to bacteria in vitro. No additional data are 

available on these cluster members.

1,2-Benzenedicarboxylic acid, 1,2-bis(2,3-dibromopropyl) ester (CASRN 7415-86-3) 

No data are available for this cluster member. 

Confidential A and Confidential B. 

Confidential A is subject to a consent order whose testing is triggered by production volume. No 

data are available for this cluster member or Confidential B. 

Commercial Products (Firemaster® 550 and Firemaster® BZ-54) 

The commercial product cited in the literature (Firemaster® 550) is comprised of a mixture of 

two of the members of the brominated phthalates cluster (TBPH and TBB) as well as two 

phosphates: triphenyl phosphate (TPP; CASRN 115-86-6) and isopropylated triphenyl phosphate 

(ITPP; CASRN 68937-41-7) (Chemtura, 2012b). Available screening-level data on these 

phosphates (ECHA, 2013; EPA, 2010b; OECD, 2002) suggest that these constituents pose a 

hazard to human health and the environment. Firemaster® BZ-54 does not have phosphates in 

its formulation (Chemtura, 2010, 2013a). 

Triphenyl phosphate (TPP; CASRN 115-86-6) 

Triphenyl phosphate (TPP) exhibits low acute toxicity via the oral (rats, mice, rabbits and guinea 

pigs) and dermal (rabbits) routes. TPP is not irritating to the skin and is slightly irritating to the

eyes. There is evidence (case reports) of skin sensitization in humans. Oral repeat dose studies 

in rats showed a slight depression in body weight gain and an increase in liver weights at 350 

mg/kg-day; the NOAEL was 70 mg/kg-day. TPP did not induce immediate or delayed 

neuropathy in hens and cats. TPP was not mutagenic in bacteria or mammalian cells in vitro. No 

adverse effects on fertility or development were found in rats fed up to 700 mg/kg-day TPP

during gametogenesis prior to mating and throughout mating and gestation. TPP did not show 

carcinogenic potential in a mouse lung adenoma assay (OECD, 2002). 

Isopropylated triphenyl phosphate (ITPP; CASRN 68937-41-7) 

The acute oral and dermal toxicity of isopropylated triphenyl phosphate (ITPP) in rats is low. 

ITPP is not irritating to rabbit skin but is irritating to rabbit eyes. ITPP was neurotoxic to hens. 

No additional data were available or considered reliable for the EPA hazard characterization 

(EPA, 2010b). In the submission to the European Chemicals Agency (ECHA, 2013), data for 

several commercial products suggest that ITPP exhibits chronic toxicity. In addition, data from 

an oral gavage reproductive/developmental toxicity screening test showed that rats treated 

with Reofos 65 exhibited poor reproductive performance at 400 mg/kg-day (only dose tested) 

(ECHA, 2013). In a combined repeated-dose/reproductive/developmental toxicity screening test 

with the same compound, rats exhibited increased ovary/oviduct, adrenal gland (males and 
Page 16 of 23 

females) and liver (males only) weights and decreased epididymal weights with corresponding 

macroscopic and/or microscopic changes in these tissues at 25 mg/kg-day. The NOAEL for 

systemic toxicity was not established. Male and female reproductive performance was also 

adversely affected at dose levels of 100 and 400 mg/kg-day, manifested by significant 

reductions in fertility and copulation/conception indices. Early postnatal development was also 

affected at dose levels of 100 and 400 mg/kg/day. The number of pups born and live litter size 

were decreased in these groups, while the numbers of pups found dead or euthanized in 

extremis were increased; all pups from five of six litters in the 400 mg/kg-day group were either 

found dead or euthanized in extremis prior to PND 4. The NOAEL for 

reproductive/developmental toxicity was 25 mg/kg-day. 

Data Needs Assessment 

The potential for exposure to the brominated phthalates cluster (BPC) members during 

chemical manufacture is not clearly understood. Similarly, there is evidence for potential 

exposure to some of the cluster members during occupational use of products containing some 

of the cluster members. There is also evidence to suggest potential consumer exposure to the 

BPC members during the use of some of the products containing some of the BPC members. 

An overview of the data for the structural analog, bis(2-ethylhexyl)phthalate (DEHP; CASRN 

117-81-7), was presented. It could be argued that conservatively, these data could be used to 

characterize the hazard for the brominated phthalates cluster (BPC) members. However, 

available data suggest that the mode of action of DEHP that elicits chronic (specifically 

reproductive and developmental) toxicity is not the same as that of the BPC members. In 

addition, the available data support this hypothesis. There is uncertainty characterizing the 

hazard for the BPC members because the chronic (including reproductive/developmental) 

toxicity observed in animal studies with the BPC members is via a mode of action not 

considered relevant to humans or at concentrations that either do not raise immediate 

concerns, or which are difficult to attribute to a particular chemical because the data were 

obtained using a commercial mixture. 

Based on the available data for TBPH, there is a low hazard for acute toxicity. In the screeninglevel dietary study in rats with TBPH (described above), the potential for liver toxicity was 

observed by perturbations in clinical chemistry values. However, some liver effects have been 

attributed to a mode of action, peroxisome proliferation (peroxisome proliferator activated 

receptor; PPARα), not considered relevant to humans (Springer et al., 2012). The repeated-dose 

study with the commercial product Firemaster® BZ-54 showed the potential for kidney effects 

at the lowest dose tested, indicating that the kidney may be a potential target organ (NICNAS, 

2004). In the two-generation reproductive toxicity study and a prenatal developmental toxicity 

study with the commercial product Firemaster® BZ-54 (TBPH/TBB mixture), showed the 

potential to affect fetal development at high doses. The uncertainty of using the data for the 

commercial product to characterize the hazard for TBPH or TBB lies in the attribution of the 

toxicity observed to either mixture component. No toxicity studies with TBB alone are available; 
Page 17 of 23 

however, given that the metabolites of TBPH and TBB are different, it is expected that any 

toxicity observed would not be by the same mode of action or attributable to the same 

chemical. Springer et al., (Springer et al., 2012) observed the potential for endocrine disruption 

with the metabolites of TBPH and TBB suggesting that the potential for 

reproductive/developmental toxicity needs to be explored further. It would also be useful to 

identify the targets organs of toxicity for TBB, if any. Screening level data do not suggest a 

concern for carcinogenicity and the potential for a mode of action not relevant to humans 

(PPARα) further lowers the potential concern and the need for data for this chronic toxicity 

endpoint. 

No data are available for CASRN 7415-86-3. The acute toxicity of CASRNs 20566-35-2 and 

77098-07-8 is considered low. No data for repeated-dose or reproductive/developmental 

toxicity are available for CASRNs 20566-35-2 and 77098-07-8. The need for human health data 

for these chemicals is dependent on the potential exposure during manufacture and the 

potential for at least CASRNs 20566-35-2 and 77098-07-8 to be released from the polymer 

backbone. 

2 ECOLOGICAL HAZARD 

Hazard Identification 

The environmental hazard of brominated phthalates reviewed and summarized in this section is 

based on studies located and reviewed from EPA’s TSCATS databases (public), public literature 

searches, and other confidential sources; information from confidential sources not already 

public were excluded from this assessment. Full study reports were not located for all identified 

studies. Available hazard data are summarized in Table 2-1 and described below. 
Page 18 of 23 

Table 2-1: Environmental Effects Data for Brominated Phthalates Cluster 

Test Substance Composi

tion 

Test 

Organism 

Species Test 

Guideline 

Duration Endpoint Value (mg/L) 

Firemaster® BZ-54 TBB/TBPH Fish Oncorhynchus 

mykiss 

OECD TG 203 96-h LC50 NES 

Daphnid Daphnia 

magna 

OECD TG 202 48-h EC50 0.42 

Daphnid Daphnia 

carinata 

 15-d ChV 0.022 

Algae Selenastrum 

capricornutum 

OECD TG 201 96-h EC50 

ChV 

NES NES 

TBPH:1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1,2-bis(2-ethylhexyl) ester

>95% TBPH

Fish Oncorhynchus 

mykiss 

OECD TG 203 96-h EC50 NES 

Daphnid Daphnia 

magna 

OECD TG 202 48-h EC50 0.3 

Daphnid Daphnia 

magna 

OECD TG 202 48-h EC50 NES 

Algae Desmodesmus 

subspicatus 

OECD TG 201 72-h EC50 

ChV 

NES NES 

PM-PHT-4 Diol: 2-(2-hydroxyethoxy) ethyl 2-hydroxy propyl 3,4,5,6 tetrabromobenzene dicarboxylate

Not Stated Fish Lepomis 

macrochirus 

EPA-660/3-75-009, April, 1975. 

96-h LC50 12 
In general, insufficient experimental data are available to characterize hazard that would result 

from chronic exposure to wildlife populations. Currently, information from experimental 

studies that address standard aquatic toxicity endpoints are limited to two chronic invertebrate 

studies conducted on two different species and two different flame retardant formulations (BZ54 and pure TBPH) that present conflicting conclusions. Additional studies are available that 

attempt to address population level effects using approaches that would not be sufficient to 

support a full risk assessment, but can be used to support qualitative hazard concerns for the 

brominated phthalates. One such study, a long term mesocosm study (de Jourdan et al., 2014; 

de Jourdan et al., 2012), demonstrates that the benthic community composition exhibited 

significantly lower diversity and greater abundance of Chironomids in cosms treated with 500 

ng BZ-54/g sediment compared to the controls and suggests aquatic and/or sediment dwelling 

invertebrate populations may be impacted by chronic exposure. 

Acute aquatic base-set toxicity data were available for TBPH/TBB that also suggest aquatic 

invertebrates as the most sensitive species; however, given the low water solubility and high 

Log Kow of TBPH/TBB and the use of solvents and/or test concentrations above the limit of 

solubility, there is concern that these effects do not represent environmental conditions. A 

single acute fish toxicity study was available for cluster members with a Log Kow of less than 5 

that suggests moderate toxicity; however, given results from TBPH/TBB, aquatic invertebrates 

are likely more sensitive than fish. Acute experimental data are not available for Confidential A 

and Confidential B, but Confidential A is subject to a consent order whose testing is triggered by 

production volume. 

Commercial products cited in the literature as containing brominated phthalates (i.e., 

Firemaster® 550 and Firemaster® BZ-54) are considered to be known mixtures of the 

brominated phthalates/esters TBPH and TBB (Firemaster® BZ-54) (Chemtura, 2013a) or 

mixtures of the brominated phthalates/esters TBPH and TBB in addition to triphenyl phosphate 

(TPP; CASRN 115-86-6) and isopropylated triphenyl phosphate (ITPP; CASRN 68937-41-7) 

(Firemaster® 550) (Chemtura, 2012b). These latter aryl phosphates are considered to have a 

mode of action unlike the brominated phthalates cluster and may exert toxic effects on 

exposed organisms different than those noted for the brominated phthalates. However, 

insufficient experimental data are available to characterize ecotoxicity of the Firemaster® 550 

formulation and, thus, a comparison of the more homogenous brominated phthalate 

formulations to the more heterogeneous aryl phosphate and brominated phthalate 

formulations cannot be made. Risk determination of aryl phosphates is outside the scope of the 

brominated phthalates data needs assessment. Screening-level data on these phosphates are 

available in (ECHA, 2013; EPA, 2010b; OECD, 2002). 

Data Needs Assessment 

The goal of this data needs assessment is to identify information that is currently needed to 

characterize environmental risk. In order to determine whether there are risks to the aquatic, 
 

Page 20 of 23 

benthic, and terrestrial environment, both hazard and exposure data are needed to address the 

following key questions: 

1. How do levels of brominated phthalates measured in effluent and surface water 

compare to levels that produce adverse effects in aquatic invertebrates, fish, or plants? 

2. How do levels of brominated phthalates measured in sediment compare to levels that 

produce adverse effects in sediment invertebrates? 

3. How do levels of brominated phthalates measured in soil compare to levels that 

produce adverse effects in soil invertebrates and plants? 

4. Given the levels of brominated phthalates detected in avian species during 

biomonitoring, what is the likely exposure route and at what level are adverse 

population level effects expected? 

5. Are there persistent or bioaccumulative degradates that may result in a hazard concern? 

Based on current knowledge of the class, the additives, i.e. TBPH, TBB and 1,2-

Benzenedicarboxylic acid, 1,2-bis(2,3-dibromopropyl) ester (CASRN 7415-86-3) are likely to 

exhibit differences in environmental mobility and bioavailability than the remaining cluster 

members (reactives) [i.e TBPA-Diol: 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1-[2-(2-

hydroxyethoxy)ethyl] 2-(2-hydroxypropyl) ester (CASRN 20566-35-2) and TBPA-Diol: 1,2-

Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, mixed esters with diethylene glycol and 

propylene glycol (CASRN 77098-07-8)]. Data needs are being assessed for the brominated 

phthalate ester clusters separately for TBPH/TBB and the remaining cluster members based on 

this perceived difference in transport and bioavailability that will affect testing 

recommendations. 

Insufficient experimental data are available to assess chronic aquatic, sediment, and terrestrial 

hazard across the brominated phthalates cluster. This includes the fish, aquatic invertebrates, 

aquatic plants, sediment dwelling organisms, terrestrial invertebrates, terrestrial plants, and 

avian taxa. Experimental data to assess all acute aquatic hazard endpoints are limited to 

chemicals with a Log Kow of > 5. These data suggest increased sensitivity to aquatic 

invertebrates with high hazard concerns even though physicochemical properties suggest 

limited bioavailability following acute exposure. Most studies reviewed used a solvent or 

emulsifier to solubilize the test substance over time in solution. Use of a solvent may confound 

the results when effects are observed, but in all cases a solvent control was included for 

comparison. 

Given the low water solubility and high log Kow of TBPH and TBB, these cluster members are 

expected to be found in the sediment, sludge and soil. Monitoring data are available that 

support predicted partitioning to sediment, soil, and sludge and suggest likely chronic exposure. 

Organisms likely exposed for which no experimental data are available include sediment 

invertebrates and terrestrial organisms (e.g., plants, invertebrates and birds). Based on the 

likely long-term exposure, chronic hazard data should be provided. Due to difficulties 

interpreting studies of mixtures, experimental data should be conducted on pure substances 

(e.g., ≥ 90 % purity). 
 

Page 21 of 23 

Likely exposure pathways based on predictive and experimental physicochemical and fate 

parameters and reported release information for TBPH and TBB suggests minimal persistence 

in the water column and limited/no processing or manufacturing releases to water due to 

regulatory action. No monitoring data are available to suggest the presences of brominated 

phthalates in surface water, but monitoring of biota in water bodies has identified TBB/TBPH in 

aquatic organisms suggesting chronic exposure ecotoxicity data for water column organisms 

are limited to two chronic aquatic invertebrate studies on TBPH and Firemaster® BZ-54 

(TBB/TBPH) that report conflicting results. Since data suggest high chronic hazard to aquatic 

invertebrates, data from additional independent chronic aquatic invertebrate studies on TBPH

and TBB are needed to verify chronic aquatic invertebrate toxicity. 

The two remaining brominated phthalates cluster members (i.e., CASRNs 20566-35-2 and 

77098-07-8) have no monitoring data, little hazard data, and represent the more soluble and 

bioavailable members of the cluster. These reactive cluster members are physically 

incorporated into end-use products and, thus, less likely to be released to the environment 

from their end-use products. Release from manufacturing and processing prior to reactive 

incorporation into the end-use product represents a potential pathway of exposure to the 

environment. Thus, further characterization of exposure pathways is needed to determine 

ecotoxicity data needs for these cluster members. 

No data are available for CASRN 7415-86-3.

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