TSCA Work Plan Chemical 

Technical Supplement – Physicochemical Properties and 

Environmental Fate 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-Q1-4001 

August 2015 

Office of Chemical Safety and 

Pollution Prevention
Page 2 of 17 

TABLE OF CONTENTS 

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

1 INTRODUCTION .............................................................................................................. 3

1.1 CHEMICAL AND PHYSICAL PROPERTIES ........................................................................................................ 4

1.1.1 Reactive BPC members ............................................................................................................................. 4

1.1.2 Additive BPC members ............................................................................................................................. 5

1.2 ENVIRONMENTAL FATE AND BIOACCUMULATION ...................................................................................... 6

1.2.1 Summary .................................................................................................................................................. 6

1.2.2 Fate in Air and the Indoor Environment ................................................................................................... 7

1.2.3 Fate in Water ............................................................................................................................................ 8

1.2.4 Fate in Soil and Sediment ....................................................................................................................... 10

1.2.5 Bioaccumulation ..................................................................................................................................... 10

1.3 ENVIRONMENTAL FATE AND BIOACCUMULATION – DATA NEEDS .............................................................. 13

1.3.1 Ambient Environment ............................................................................................................................. 13

1.3.2 Indoor Environment ................................................................................................................................ 14

REFERENCES ........................................................................................................................ 14

LIST OF TABLES 

Table 1-1: Physicochemical properties of TBPH ............................................................................. 5

Table 1-2: Physicochemical Properties of TBPA Diol ...................................................................... 5

Table 1-3: Environmental Fate Data for the Brominated Phthalates Cluster .............................. 11

TABLE OF FIGURES 

Figure 1-1: Generic Structure of the Brominated Phthalates Cluster Chemicals ........................... 3

Figure 1-2: Generic structure of the BPC members and CASRN 7415-86-3 ................................... 4
Page 3 of 17 

1 INTRODUCTION 

Each chemical in this cluster has several structural features in common: 

1) Multiple bromine atoms, typically attached to the aromatic ring 

2) The 1,2-benzenedicarboxylate moiety (phthalate structure)1

 and 

3) Alkyl esters 

Br O 

Br

O Alkyl

O 

Br

Br O

Alkyl

Figure 1-1: Generic Structure of the Brominated Phthalates Cluster Chemicals 

Some members of the cluster have free primary or secondary alcohol functionalities. These 

may impart certain properties to the chemical substance [making them more water soluble and 

chemically reactive], more significantly the alcohol moiety can react to incorporate the 

brominated (BFR) into the substrate via covalent bond formation. These chemicals are not 

limited to that reactive form of application and they could also be mixed with substrate as an 

additive flame retardant (FR). 

The one cluster member is an anomaly when compared to the structure of the other cluster 

member chemicals, bis (2,3-dibromopropyl) 1,2-benzenedicarboxylic acid (CASRN 7415-86-3). 

The primary difference between this chemical and the other cluster members is the positioning 

of the four (4) bromine atoms (on the alkyl ester moieties) as opposed to the positions on the 

benzene ring. 

 

1

The cluster member 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB; CASRN 183658-27-7) is missing one of 

the phthalate carboxylate ester but is including in this cluster since the commercial product Firemaster 550 

also contains the TBB / TBPH phthalate mixture. This structural anomaly should not affect the inclusion of this 

chemical since phthalates often decarboxylate during metabolism and biodegradation. (Robbert 

Kleerebezem*, 1999)
Page 4 of 17 

Br O

Br

O

O 

Br 

Br O 

Alkyl 

Alkyl 

O Br Br

O 

O 

O Br Br

Figure 1-2: Generic structure of the BPC members and CASRN 7415-86-3 

1.1 CHEMICAL AND PHYSICAL PROPERTIES 

1.1.1 Reactive BPC members 

The reactive members of the BPC are 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1-[2-

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

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

propylene glycol (TBPA-Diol; CASRN 77098-07-8). 

Because these chemicals are chemically bound to the polymer, it is far less likely they will 

migrate from products or articles unless there is excess chemical present due to an incomplete 

polymerization reaction. The reactive members of the brominated phthalates cluster (BPC), 

including the primary degradation product tetrabromophthalic acid, have not been reported in 

literature as being present in environmental or biological media. 

The brominated phthalates with hydroxyalkyl esters are generally intended to react with 

isocyanate monomers and become covalently bonded into the chemical backbone of the 

polyurethane foams (PUF). There is no evidence of the phthalate esters based urethane 

linkages ever depolymerizing under abiotic, biotic, or metabolic conditions. One may anticipate 

that if depolymerization were to occur the ester linkage would cleave before the carbamate 

linkage generating the tetrabromophthalate diacid as a predominant product. There has been 

no monitoring data indicating the presence of hydroxyalkyl tetrabromophthalates in the 

environment or biota. As such worker exposures would be the main concern during chemical 

manufacturing and PUF manufacturing. The esters are liquids with negligible vapor pressure 

and limited but measurable water solubility because of the hydroxyl and/or other oxygen 

atoms in the molecule [one MSDS states < 1 g/L; the estimates are substantially lower than this 

number but seem unreasonable). In one patent [Crain and Surma, 2010] , it is noted that both 

reactive and additive BPC chemicals can be added to foam, which would again lead to potential 

release of one type of BPC while the reactive BPC would be self contained in the foam 

backbone . 
Page 5 of 17 

1.1.2 Additive BPC members 

The additive members of the BPC are 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1,2-

bis(2-ethylhexyl) ester (TBPH; CASRN 26040-51-7), benzoic acid, 2,3,4,5-tetrabromo-, 2-

ethylhexyl ester (TBB; CASRN 183658-27-7) and 1,2-Benzenedicarboxylic acid, 1,2-bis(2,3-

dibromopropyl) ester (CASRN 7415-86-3). 

Additive flame retardants are incorporated and dispersed throughout a product, but are not 

chemically bound to it. Additive flame retardants are more likely than reactive flame 

retardants to migrate from products or articles. Emissions from a single product or article may 

be small. However, combined emissions from all sources within various indoor 

microenvironments, residences, schools, public and commercial buildings, cars, trains, 

airplanes, may be significant. 

TBPH and TBB are liquids with negligible vapor pressure and water solubility. They have the 

same functional groups and may be considered close analogs of one another. 

There are few measured physicochemical properties values for Melting Point, Boiling Point, 

Vapor Pressure, Water Solubility or Octanol Water Partition Coefficient for these chemicals. 

The MSDS sheet (Unitex, 2006) for pure TBPH provides some range limits for the cluster as does

the water solubility [1.3 mg/L at 25°C, (ECHA, 2013)] for the unbrominated di(2-ethylhexyl) 

phthalate (DEHP) ; while the more water soluble products [hydroxyl containing] are represented 

by CASRN 77098-07-8, a submission under the HPV Challenge program (Albemarle - GLCC, 

2004). 

Table 1-1: Physicochemical properties of TBPH 

Compound MP BP VP s-H2O Log Kow

TBPH < -20 °C > 400 °C < 1.0 E-3 Torr 

 at 25 °C insoluble 9.34 

(ACD est.) 

Source: Unitex Chemical Corp. Uniplex FRP-45 MSDS (Unitex, 2006) 

Table 1-2: Physicochemical Properties of TBPA Diol 

Compound MP B

P

V

P

s-H2O Log Kow

CASRN

77098-07-8 

NA N

A

< 1E-6 Torr 

(est.) 

< 1

g/L 

MS

3.83

(EPI est.)

Source: EPA HPV Challenge Program submission (Albemarle - GLCC, 2004) 

CASRN 7415-86-3 

No data were located for this cluster member. 
Page 6 of 17 

In addition to the chemicals already described, Confidential A, and Confidential B can be 

considered analogous to the other cluster members described here. There was little to no 

physicochemical data, and structures for these chemicals are similar enough to use read across. 

1.2 ENVIRONMENTAL FATE AND BIOACCUMULATION 

1.2.1 Summary 

Very little information exists on the environmental fate and bioaccumulation of the brominated 

phthalates cluster (BPC) members. 1,2-Benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, 1,2-bis(2-

ethylhexyl) ester (TBPH) and benzoic acid, 2,3,4,5-tetrabromo-, 2-ethylhexyl ester (TBB) are the 

best studied and may be considered close analogs of one another. Based on available data, 

both compounds are ranked low for persistence (P1) relative to standard criteria (EPA, 1999b). 

The tetrabrominated microbial degradation and/or hydrolysis products tetrabromophthalic acid 

and tetrabromobenzoic acid are expected to be much more persistent and are ranked as P3. 

Estimated bioaccumulation factors (BAFs) suggest that TBPH and TBB have low (B1) and 

moderate bioaccumulation potential (B2), respectively. The phthalic and benzoic acid products 

are also considered to have low (B1) and moderate bioaccumulation potential (B2), 

respectively. 

TBPH and TBB are expected to have low mobility in soil. Biodegradability is not well 

characterized but based on available data, half-lives for primary degradation in water may be 

on the order of days. Primary biodegradation of TBPH and TBB is expected to yield the 

monoethylhexyl ester of tetrabromophthalic acid and tetrabromobenzoic acid as the main 

products, respectively. Abiotic hydrolysis may occur, but the low solubility of TBPH and TBB

may lower the effective rate of hydrolysis in the environment. Based on estimated half-lives 

and considering the low water solubility, rates of abiotic hydrolysis are expected to be 

negligible at environmental pH and temperatures. The ultimate hydrolysis products of TBPH

and TBB, 3,4,5,6-tetrabromo- 1,2-benzenedicarboxylic acid (i.e. tetrabromophthalic acid) and 

tetrabromobenzoic acid, are expected to be resistant to further abiotic transformations as well 

as biodegradation and may be persistent in the environment. The rate of atmospheric gasphase (hydroxyl radical) photo-oxidation has the potential to be moderate; however, these 

substances are expected to exist primarily in the particulate phase in the ambient atmosphere, 

and generally it is assumed that oxidation of particle-bound substances is slow or negligible. 

Particulate-phase TBPH and TBB are expected to be removed from the atmosphere by wet and 

dry deposition processes. TBPH and TBB absorb light at environmentally significant 

wavelengths, but the importance of this process for environmental waters has not been 

established. These chemicals have the potential to be transported far from their original point 

of release, primarily in the atmospheric particle-bound form. 

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

hydroxypropyl) ester and 1,2-benzenedicarboxylic acid, 3,4,5,6-tetrabromo-, mixed esters with 
Page 7 of 17 

diethylene glycol and propylene glycol (CASRNs 77098-07-8 and 20566-35-2) are expected to 

have high mobility in soil. Estimated abiotic hydrolysis half-lives for this substance are lower 

than for TBPH and TBB (on the order of days to months depending on the estimation program), 

but these values are still considered to be in the slow-to-negligible category (EPA, 2012f). No 

biodegradation data were available for this substance. Given its molecular structure this 

substance would not be expected to be readily biodegradable, but both abiotic hydrolysis and 

biodegradation may produce the same brominated degradation product as for TBPH; namely 

tetrabromophthalic acid. As for TBPH and TBB, the estimated rate of atmospheric 

photooxidation is moderate; however, this is not expected to be an important environmental 

degradation pathway. Given the estimated rate of hydrolysis, CASRN 77098-07-8 is expected to 

have low persistence (P1) and low bioaccumulation potential (B1). However, the degradation 

product tetrabromophthalic acid is expected to have high persistence (P3) and low 

bioaccumulation potential (B1). 

No measured environmental fate data exist for 1,2-benzenedicarboxylic acid, 1,2-bis(2,3-

dibromopropyl) ester, CASRN 7415-86-3. Both estimated vapor pressure and volatility, based 

on estimated Henry’s Law constant, are low. This substance is expected to partition strongly to 

environmental solid phases (in sludge, soil, etc.) and have low-to-moderate mobility in soil. 

Based on chemical structure and estimated data hydrolysis may occur, but the rate is expected 

to be negligible. Given its molecular structure this substance would not be expected to be 

readily biodegradable. Atmospheric photooxidation is expected to be slow. This substance is 

estimated to be moderately persistent (P2) and bioaccumulative (B2). Hydrolysis, if it occurs, 

may yield 2,3-dibromopropanol as a product, but neither this nor any other hydrolysis products 

are expected to have PBT properties. 

1.2.2 Fate in Air and the Indoor Environment 

BPC members have low-to-negligible vapor pressures and low-to-negligible volatility, and as a 

result, inhalation of volatilized (gas phase) substances is expected to be a minor route of indoor 

exposure for all BPC members. In contrast exposure via dust may be important, but little 

information is available on how these compounds get into house dust. This process may 

involve direct transfer from flame-retarded objects, driven by partitioning properties of the 

substances. Measured concentrations of TBPH (Ali et al., 2012; Allen et al., 2013a; Allen et al., 

2013b; Bradman et al., 2012; Dodson et al., 2012; Gheorghe et al., 2013; Johnson et al., 2013; 

Kopp et al., 2012; Sahlstrom et al., 2012; Schlabach et al., 2011; Shoeib et al., 2012; Springer et 

al., 2012; Stapleton et al., 2008a; Stapleton et al., 2009; Stapleton et al., 2008b; Van den Eede 

et al., 2012) and TBB (Ali et al., 2012; Allen et al., 2013a; Allen et al., 2013b; Bradman et al., 

2012; Dodson et al., 2012; Gheorghe et al., 2013; Johnson et al., 2013; Kopp et al., 2012; 

Sahlstrom et al., 2012; Schlabach et al., 2011; Shoeib et al., 2012; Springer et al., 2012; 

Stapleton et al., 2008a; Stapleton et al., 2009; Stapleton et al., 2008b; Van den Eede et al., 

2012) in indoor air and dust are consistent with these predictions. The relative contributions of 

indoor air and dust to overall exposure indoors are expected to be similar to that reported for 

polybrominated diphenyl ethers (PBDEs) in the indoor environment (Webster et al. 2013), for 

which dust was considered important but indoor air not. 
Page 8 of 17 

If released to the ambient atmosphere, these compounds are expected to exist primarily in the 

particulate phase, given their estimated vapor pressures. Consequently, the photochemically 

catalyzed vapor phase reaction with hydroxyl radicals (for which half-lives are given in Table 

1-3) is not expected to be environmentally relevant. Davis and Stapleton (2009) measured halflives for photodegradation of TBPH and TBB by sunlight in several organic solvents. Half-lives 

for photodegradation of TBPH in toluene, methanol, and tetrahydrofuran were 147, 220 and 

168 min, respectively. For TBB the values were 162, 95, and 85 min. These results suggest that 

both substances absorb light and photodegrade at environmentally important wavelengths, 

although for water the importance of this process is not known. 

In the particulate phase, they may be subject to removal from the atmosphere via wet or dry 

deposition. TBB and TBPH have the potential to be transported far from their original point of 

release (Harju et al., 2009), but their atmospheric transport behavior is determined by the 

transport behavior of the particles to which they sorb. A study of arctic biota by Harju et al. 

(2009) provides supporting evidence of long-range transport. In an air monitoring study TBPH

and TBB were detected at high frequency in samples collected from North America, Central and 

South America, Europe, Africa, Asia, and Australia (Lee et al., 2010), providing additional 

evidence for the ability of these substances to enter the atmosphere and undergo long-range 

transport. 

CASRNs 77098-07-8 and 20566-35-2, and CASRN 7415-86-3 are expected to behave similarly to 

TBPH and TBB in the atmosphere. The estimated Henry’s Law constants are negligibly low 

(Table 1-3) and as a result, they are not expected to volatilize from water or soil. However, 

even if released to the atmosphere, they are expected to exist primarily in the particulate 

phase. Consequently, the photochemically catalyzed vapor phase reaction with hydroxyl 

radicals is not expected to be environmentally relevant. 

1.2.3 Fate in Water 

If released to water, TBPH and TBB are expected to adsorb to sediment and suspended 

particulate matter, based upon the estimated Koc values (Table 1-3). Volatilization from water 

is not expected to be an important environmental fate process given the estimated Henry’s Law 

constants. Abiotic hydrolysis may occur, but the low solubility of TBPH and TBB may lower the 

effective rate of hydrolysis in the environment. Based on estimated half-lives and considering 

the low water solubility, rates of abiotic hydrolysis are expected to be negligible at 

environmental pH and temperature. The ultimate hydrolysis products of TBPH and TBB, 

3,4,5,6-tetrabromo- 1,2-benzenedicarboxylic acid (i.e. tetrabromophthalic acid) and 

tetrabromobenzoic acid, respectively, are expected to be resistant to further abiotic 

transformation as well as biodegradation and may be persistent in the environment. 

TBPH was not readily biodegradable in one test, achieving less than 4% of its theoretical oxygen 

demand after 28 days in a test with inoculum from secondary effluent from a tricking filter at a 

sewage treatment plant that received predominantly domestic waste (Table 1-3). It is unclear 
Page 9 of 17 

whether these results represent a combination of a closed bottle test (OECD TG 301D) and a 

modified Sturm test (OECD TG 301B), or two separate tests. In a separate Porous Pot test 

(OECD TG 303A) conducted using a commercial mixture of TBPH and TBB, these substances did 

not biodegrade but did show substantial total removal (>= 93%) by sorption to sludge. 

Primary biodegradation of TBPH and TBB is expected to yield the monoethylhexyl ester of 

tetrabromophthalic acid and tetrabromobenzoic acid as the main products, respectively. A 

shake-flask die-away study (OCSPP 835.3170) of the same commercial mixture yielded half-lives 

for disappearance of the starting material of 3.5 days and 8.5 days in active water and active 

sediment test systems, respectively. Neither ultimate degradation nor other possible 

metabolites were measured in this test. 

Recently de Jourdan et al. (de Jourdan et al., 2013) studied the fate of TBPH and TBB in aquatic 

mesocosms, which are designed to closely simulate environmental conditions. This type of 

study can be considered a higher tier (more realistic) form of simulation test, in comparison to 

die-away studies as summarized above. The median dissipation times (DT50) differed in the 

two compartments, with more rapid disappearance in the particulate (9–30 d) than in the 

sediment compartment (>100 d) for each compound. The degradation products were more 

concentrated in the particulate compartment and corresponded to known photodegradation 

products. The ratio of TBB to TBPH differed in the mesocosm compartments compared with 

the starting test material, indicating increased degradation of TBB relative to TBPH. In the dieaway test (discussed in the preceding paragraph) the “active sediment” treatment had a low 

level of suspended sediment in natural water; thus it is analogous to the “particulate phase” 

treatment in the de Jourdan et al. (de Jourdan et al., 2013) mesocosm study. The reported 

DT50s of 9-30 d for the particulate compartment therefore can be compared to the 8.5-day 

half-life for the “active sediment” die-away treatment. The higher DT50s observed in the 

“sediment phase” portion of the mesocosm study would be expected, given that as a rule, 

organic chemicals degrade more slowly under the anaerobic conditions prevalent in benthic 

sediments. 

Davis and Stapleton (Davis and Stapleton, 2009) measured half-lives for photodegradation of 

TBPH and TBB by sunlight in several organic solvents. Half-lives for photodegradation of TBPH

in toluene, methanol, and tetrahydrofuran were 147, 220 and 168 min, respectively. For TBB

the values were 162, 95, and 85 min. These results suggest that both substances absorb light 

and photodegrade at environmentally important wavelengths, but the importance of this 

process for the water environment is not known. The observation by de Jourdan et al. (2013) 

that mesocosm degradation products corresponded to known photodegradation products is 

consistent with Davis and Stapleton (Davis and Stapleton, 2009), but again, photodegradation 

has not been directly studied under environmentally relevant conditions. 

Estimated abiotic hydrolysis half-lives for 3,4,5,6-tetrabromo-1,2-benzenedicarboxylic acid, 

mixed esters with diethylene glycol and propylene glycol (CASRNs 77098-07-8 and 20566-35-2) 

are lower than for TBPH and TBB (on the order of days to months depending on the estimation 

program), but still considered to be in the slow-to-negligible category. No biodegradation data 
Page 10 of 17 

were available for this substance. Given its molecular structure it would not be expected to be 

readily biodegradable, but both abiotic hydrolysis and biodegradation may produce the same 

brominated degradation product as for TBPH; namely tetrabromophthalic acid. The 

nonbrominated ester hydrolysis product(s) of 3,4,5,6-tetrabromo-1,2-benzenedicarboxylic acid, 

mixed esters with diethylene glycol and propylene glycol are expected to be rapidly 

biodegradable under all conditions. 1,2-(2,3-Dibromopropyl) benzene dicarboxylate (CASRN 

7415-86-3) is estimated to hydrolyze abiotically more slowly than other cluster members (i.e. at 

a negligible rate) but is similarly not expected to be readily biodegradable. Abiotic or 

biologically catalyzed hydrolysis, if either occurs, may yield 2,3-dibromopropanol as a product. 

1.2.4 Fate in Soil and Sediment 

If released to soil, TBPH and TBB are expected to have low mobility, based on their estimated 

log Koc values. Estimated Koc values for 1,2-(2,3-dibromopropyl) benzene dicarboxylate (CASRN 

7415-86-3) are just below the threshold for low/moderate mobility, suggesting that mobility 

may be characterized as low-to-moderate for this cluster member. In contrast, 3,4,5,6-

tetrabromo-1,2-benzenedicarboxylic acid, mixed esters with diethylene glycol and propylene 

glycol (CASRNs 77098-07-8 and 20566-35-2) is expected to have high mobility in soil. The 

biodegradation studies and other evidence discussed above suggest that ultimate degradation 

of the brominated benzoic and phthalic acid degradation products of BPC members is likely to 

be slow. One study is available for tetrabromophthalic anhydride (CASRN 632-79-1), which 

would be quickly hydrolyzed to tetrabromophthalic acid (CASRN 13810-83-8) in the 

environment, and it showed no degradation in 28 days (Butz, 1979). The nonbrominated 

products that would be formed from biological or abiotic hydrolysis of the parent materials are 

expected to biodegrade easily under all environmental conditions. Volatilization from moist soil 

surfaces is expected to be low given the negligibly low estimated Henry’s Law constants (Table 

1-3). Hydrolysis may be an important environmental fate process in moist soil but this requires 

experimental confirmation. 

Davis (Davis, 2013) studied the fate of TBPH and TBB in greenhouse experiments. These 

compounds were found to resist degradation biosolids-amended, in non-vegetated soil, but in 

biosolids-amended soil planted with alfalfa, 43% of TBPH was lost in 28 days in the high 

biosolids-amended pots. It was stated that no clear evidence of phytoaccumulation was 

observed, suggesting that TBPH loss was due to degradation in the soil. 

1.2.5 Bioaccumulation 

A commercial mixture of TBPH and TBB served as the test substance in a rainbow trout 

bioconcentration study. The whole-fish measured bioconcentration factor (BCF) for the 

mixture was 2.02 (log BCF = 0.31). Steady state was achieved in that study, which used uptake 

and depuration periods of 35 and 14 d, respectively. Estimated BAFs (BCFBAF v3.00) suggest 

low bioaccumulation potential (B1) for TBPH but moderate potential (B2) for TBB (Table 1-3). 

BCFBAF calculates a metabolic transformation half-life normalized to a 10g fish and the ester 

linkage has the largest negative fragment coefficient, suggesting this may be the primary site of 
Page 11 of 17 

transformation for TBPH and TBB. However, metabolic biotransformation via debromination in 

fish could also reduce bioaccumulation (Stapleton et al., 2004). (Sagerup et al., 2010) observed 

apparent trophic magnification of TBB, but not TBPH, in an Arctic food chain in Svalbard, 

Norway. The food chain included one fish species, capelin (Mallotus villosus); three seabird 

species: common eider (Somateria mollissima), Brünnich’s guillemot (Uria lomvia), and blacklegged kittiwake (Rissa tridactyla); and three mammalian species: ringed seal (Phoca hispida), 

Arctic fox (Vulpes lagopus), and polar bear (Ursus maritimus). TBB was detected in all seven 

species and TBPH in five of the seven species at ng/g levels. Lipid-adjusted concentrations did 

not scale with trophic level with the exception of TBB, which was detected in polar bears at 

414.8 ng/g lipid weight, more than 30 times its concentration in primary prey (ringed seal). 

TBPH was not detected in polar bears. 

Estimated BAFs for the possible microbial degradation and/or hydrolysis products 

tetrabromophthalic acid and tetrabromobenzoic acid are below numerical thresholds for 

bioaccumulation concern; i.e. they are formally B1 (Table 1-3). However, it should be noted that 

for the benzoic acid the calculated BAF for upper trophic-level fish is close to the B2 criterion 

(i.e. log BAF = 3.00). Without metabolism, the predicted log BAF is 5.18, which exceeds the 

threshold for high concern (B3). Based on the above results this expected chief degradation 

product of TBB is considered to have moderate bioaccumulation potential (B2). This is 

appropriate also because this substance is judged likely to be much more persistent in the 

environment than the parent, thus increasing its potential to reach and accumulate in 

organisms. 

There are no experimental data for 3,4,5,6-tetrabromo-1,2-benzenedicarboxylic acid, mixed 

esters with diethylene glycol and propylene glycol (CASRNs 77098-07-8 and 20566-35-2), but 

based on chemical structure and estimated BCF and BAF (Table 1-3), bioaccumulation potential 

is considered low (B1) for the parent substance. Bioaccumulation potential is also judged to be 

low for all potential hydrolysis products. 

Similarly there are no experimental bioaccumulation data for 1,2-(2,3-dibromopropyl) benzene 

dicarboxylate (CASRN 7415-86-3). Both estimated BCF and BAF (the latter with metabolism 

included) miss the threshold for moderate concern (log=3; Table 1-3), although the regressionbased log BCF is close to the concern level. With metabolism excluded, the predicted log BAF 

exceeds the threshold for high concern (B3). Based on these results, 1,2-(2,3-dibromopropyl) 

benzene dicarboxylate (CASRN 7415-86-3) is judged to have moderate bioaccumulation 

potential (B2). 

Table 1-3: Environmental Fate Data for the Brominated Phthalates Cluster 
Page 12 of 17 

Property Brominated Phthalate Cluster Members

Chemical Name 1,2-

Benzenedicarbox

ylic acid, 3,4,5,6-

tetrabromo-, 1,2-

bis(2-ethylhexyl) 

ester 1

Benzoic acid, 

2,3,4,5-

tetrabromo-, 2-

ethylhexyl ester

1,2-

Benzenedicarboxyl

ic acid, 3,4,5,6-

tetrabromo-, 1-[2-

(2-

hydroxyethoxy)eth

yl] 2-(2-

hydroxypropyl) 

ester 4

1,2-

Benzenedicarb

oxylic acid, 

3,4,5,6-

tetrabromo-, 

mixed esters 

with diethylene 

glycol and 

propylene 

glycol 

1,2-

Benzenedicarbo

xylic acid, 1,2-

bis(2,3-

dibromopropyl) 

ester

CASRN 26040-51-7 183658-27-7 20566-35-2 77098-07-8 7415-86-3 

Photooxidation 

Half-life

5.8 hours 

(estimated)2

11.7 hours 

(estimated)2 

4.2 hours 

(estimated)2

See 20566-35-2 5.8 hours 

(estimated)2

Hydrolysis HalflifepH 7 = 29 days 

(estimated)2;

pH 8 = 2.9 days 

(estimated)2

pH 7 = 34 days 

(estimated)2;

pH 8 = 3.4 days 

(estimated)2

pH 7 =7.9 days 

(estimated)2

;

pH 8 = 19 hours 

(estimated)2

See 20566-35-2 pH 7 = 315 days 

(estimated)2;

pH 8 = 31.5 days 

(estimated)2

Biodegradation 

(ready 

biodegradation 

test data; see 

text for 

additional 

information)

<4% 

biodegradation 

after 28 day (not 

readily 

biodegradable)1,3

No data 

6% in 28 days in 

301D (BFR 

database, 

confidential data, 

described as 

adequate 

guideline study) 

No Data See 20566-35-2 No Data

Bioconcentration 

Factor

Log BCF = 1.1 

(estimated)2 

1.7-6.2 (not log; 

BFR database, 

confidential data, 

described as 

adequate 

guideline study)

Log BCF = 3.27 

(estimated)2 

Log BCF = 1.94 

(estimated)2 

See 20566-35-2 Log BCF = 2.87 

(estimated)2 

Bioaccumulation 

Factor5

Log BAF = 0.38 

(estimated)2 

Log BAF = 3.32 

(estimated)2 

Log BAF = 0.82 

(estimated)2

See 20566-35-2 Log BAF = 1.10 

(estimated)2 

Log BAF = 4.79 

(estimated; 

without 

metabolism)

Log Koc 5.9 (estimated, 

MCI method)2 

7.4 (estimated, 

log Kow method)

2

4.5 (estimated, 

MCI method)2 

5.7 (estimated, log 

Kow method) 2 

1.0 (estimated, 

MCI method)2 

2.0 (estimated, log 

Kow method) 2

See 20566-35-2 3.5 (estimated, 

MCI method)2 

3.5 (estimated, 

log Kow 

method) 2

Henry’s Law 

Constant 

(atm-m3/mol)

3.1×10-7

(estimated, group 

estimate)2 

7.1×10-6

(estimated, group 

estimate)2

2.2×10-21

(estimated, group 

estimate)2

See 20566-35-2 2.8×10-14

(estimated, 

group estimate)2
Page 13 of 17 

Property Brominated Phthalate Cluster Members

Chemical Name 1,2-

Benzenedicarbox

ylic acid, 3,4,5,6-

tetrabromo-, 1,2-

bis(2-ethylhexyl) 

ester 1

Benzoic acid, 

2,3,4,5-

tetrabromo-, 2-

ethylhexyl ester

1,2-

Benzenedicarboxyl

ic acid, 3,4,5,6-

tetrabromo-, 1-[2-

(2-

hydroxyethoxy)eth

yl] 2-(2-

hydroxypropyl) 

ester 4

1,2-

Benzenedicarb

oxylic acid, 

3,4,5,6-

tetrabromo-, 

mixed esters 

with diethylene 

glycol and 

propylene 

glycol 

1,2-

Benzenedicarbo

xylic acid, 1,2-

bis(2,3-

dibromopropyl) 

ester

Fugacity

(Level III Model)2

Air (%)

Water (%)

Soil (%)

Sediment (%)

0.169 

11.6 

88.2 

<0.1 

0.319 

11.8 

86.9 

0.95 

0.001 

37 

62.9 

0.09

See 20566-35-2

0.00000066 

11.1 

87 

1.9

1

 Brominated Phthalate Ester Panel (BR PEP) American Chemistry Council. August 5, 2004. Revised Robust Summary 

and Test Plan for Phthalic Acid Tetrabromo Bis 2-Ethylhexyl Ester (CASRN 26040-51-7). Prepared by Health & 

Environmental Horizons, Ltd. Available online from: http://www.epa.gov/hpv/pubs/summaries/phthacid/c15484tc.htm

as of June 23, 2010. 

2

 EPA. 2012. Estimation Programs Interface SuiteTM for Microsoft® Windows, v4.11. Environmental Protection Agency, 

Washington, DC, USA. Available online from: http://www.epa.gov/opptintr/exposure/pubs/episuitedl.htm. 

3

 Test substance used in the biodegradation study is indicated by the sponsor as Pyronil 45 with a purity of 95%. 

4

 ECHA: http://apps.echa.europa.eu/registered/data/dossiers/DISS-9ea569d1-072b-18ab-e044-00144f67d031/DISS9ea569d1-072b-18ab-e044-00144f67d031_DISS-9ea569d1-072b-18ab-e044-00144f67d031.html ; — indicates no data 

or no reliable data for this endpoint 

5

 Estimated upper trophic log BAF from the BCFBAF program (in Estimation Programs Interface SuiteTM for Microsoft® 

Windows, v4.11; see footnote 2. Estimates include metabolism except as noted.

1.3 ENVIRONMENTAL FATE and BIOACCUMULATION – DATA 

NEEDS 

1.3.1 Ambient Environment 

Very little information exists on the environmental fate and bioaccumulation of the Brominated 

Phthalates Cluster (BPC) members, and what data do exist, are for TBPH and TBB only. 

Therefore, comprehensive studies are needed for many endpoints and for all cluster members. 

All cluster members should be tested individually and all major degradation products should be 

quantified. This means that it is necessary to test TBB and TBPH separately. There is no point in 

testing using standard ready or inherent biodegradability tests. Among published guidelines, 

only simulation tests such as OECD TG 307 (aerobic and anaerobic soil transformation) and 

OECD TG 308 (aerobic and anaerobic transformation in aquatic sediment) are likely to yield 

information useful for informing environmental exposure (therefore, risk) assessment. Based 

on photodegradation studies of TBPH and TBB using organic solvents, cluster members may 

undergo direct photolysis; however additional work is needed to confirm this. These studies 

should measure rates and products under relevant conditions (i.e. with water as solvent). In 
Page 14 of 17 

addition, to provide needed information on key environmentally important physical properties, 

Henry’s Law constant, Koc and Koa should be determined experimentally using standard 

protocols and under GLP conditions. Comprehensive bioaccumulation studies are needed for all 

BPC cluster members, and these should include several aquatic and terrestrial species selected 

from organisms commonly used in bioaccumulation testing. Specialized protocols are available 

for some of the above endpoints and may be adapted for BPC members; e.g. the aerobic/ 

anaerobic sediment testing methodology developed for decaBDE under the PBDE SNUR. 

1.3.2 Indoor Environment 

It is EPA’s judgment that exposure via dust may be important, yet little information is available 

on how these compounds get into house dust. This process may involve direct transfer from 

flame-retarded objects, driven by partitioning properties of the Brominated Phthalates Cluster 

(BPC) substances. To better understand these processes, and therefore more accurately assess 

indoor exposure, it is necessary to conduct studies to determine rates of migration of cluster 

members from flame-retarded indoor objects; and rates and mechanisms of partitioning into 

dust and any other media that may be vectors for human exposure. 

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