TABLE D2.

Summary of the outcomes of toxicological studies of TBBPA‐bDiBPrE, the only TBBPA derivative considered in the TORs for which toxicity data have been identified, in experimental animals.

Reference	Purity Supplier (lot number)	Species tested (strain) Number of animals per dose group Age Gender	Route of administration Exposure doses Vehicle Study duration	Parameter(s) studied and effects reported	NOAEL/LOAEL
NTP et al. (2017). Tetrabromobisphenol A‐biS(2,3‐dibromopropyl ether) (CASRN 21850–44‐2) administered by gavage to F344/NTac rats and B6C3F1/N mice	Purity: 94% Great Lakes Chemical Corporation (534106)	Rats (F344/NTac) 2 × 10 animals per sex and group 5–6 weeks at study start M, F	Oral (gavage) 0, 62.5, 125, 250, 500, 1000 mg/kg bw (0, 45, 89, 179, 357, 714 mg/kg bw per day) Vehicle: corn oil Duration: 23‐days, 5‐days/week 14‐weeks, 5‐days/week	Effects at ≥ 125 mg/kg bw: – Increased microsomal protein levels (M, F) – Decreased activity of A4H, EROD, PROD, UDP‐GT (M, F) No effects up to 1000 mg/kg bw on: clinical findings, changes in clinical chemistry parameters, haematology or effects on body weights, absolute and relative‐to‐body organ weights (see methods). There were no gross or histologic lesions, changes in the number of sperm or spermatids, sperm motility or oestrus cycle	NOAEL = 714 mg/kg bw per day [on the basis that microsomal protein and enzyme changes are not adverse]
	Purity: 94% Great Lakes Chemical Corporation (534106)	Mice (B6C3F1/N) 10 animals per sex and group 6–7 weeks at study start M, F	Oral (gavage) 0, 125, 250, 500, 1000, 2000 mg/kg bw (0, 89, 179, 357, 714, 1429 mg/kg bw per day) Vehicle: corn oil Duration: 14‐weeks, 5‐days/week	Effects at ≥ 250 mg/kg bw: – Increased microsomal protein levels (M, F) – Decreased activity of A4H, EROD (M, F) – Decreased activity of UDP‐GT (F) Effects at ≥ 125 mg/kg bw: – Decreased activity of PROD (M, F) No effects up to 2000 mg/kg bw per day on: clinical findings, changes in clinical chemistry parameters, haematology or effects on body weights, absolute and relative‐to‐body organ weights (see methods). There were no gross or histologic lesions, changes in the number of sperm or spermatids, sperm motility or oestrus cycle	NOAEL = 1429 mg/kg bw per day [on the basis that microsomal protein and enzyme changes are not adverse]
Shockley et al. (2020a). Comparative toxicity and liver transcriptomics of legacy and emerging brominated flame retardants following 5‐day exposure in the rat	Purity: 94.5% Great Lakes Chemical Corporation (534106)	Rats (Harlan SD) 6 animals per dose group 7 weeks old M	Oral (gavage) 0, 0.1, 1, 10, 100, 1000 μmol/kg bw per day (corresponding to 0, 0.09, 0.94, 9.4, 94, 944 mg/kg bw per day) Vehicle: corn oil Duration: 5 days Necroscopy 1 day after the last dose	No statistically significant effects on mortality, body weight, liver weight or histopathological changes in the liver Decrease in T4 at the top dose (74% of control) No significant liver disease related transcript changes	NOAEL = 94 mg/kg bw per day LOAEL = 944 mg/kg bw per day
Yao et al. (2021). Toxicity of Tetrabromobisphenol A and its derivative in the mouse liver following oral exposure at environmentally relevant levels	Purity: NR NR (NR)	Mice (C57BL/6) 5–7 animals per group 8 weeks old M	Oral (gavage) 0, 50 μg/kg bw Vehicle: olive oil Duration: assessment at 6h after single gavage, 24 h after single gavage, and after daily exposure for 7 consecutive days	No histopathological changes in the liver, and no alterations in hepatic enzymes (ALT and AST) in the serum	NOAEL = 50 μg/kg bw
Li, Xiong, Zhang, et al. (2023). Tetrabromobisphenol A‐bis (2, 3‐dibromopropyl ether) impairs postnatal testis development in mice: the microtubule cytoskeleton as a sensitive target	Purity: > 98% MREDA (NR)	Mice (CD‐1) 15 dams (10 M pups/dam) Age: 0–56 days PND7: 3 pups/group PND21: weaning PND21‐56: 1 M pup/5 litter/group	Oral (drinking water) 0, 150, 3000 ng/mL (expected doses: 0, 50, 1000 μg/kg bw per day) Solvent: DMSO Estimated by the authors as equal to: Dams: 0, 59 ± 9, 1195 ± 150 μg/kg bw per day Weaned pups: 0, 50 ± 9, 1117 ± 172 μg/kg bw per day Duration: PND0–56	TBBPA‐bDiBPrE was detectable in serum from suckling pups on PND14 demonstrating that pups are exposed to TBBPA‐bDiBPrE through milk from the treated dams PND7: decrease body weight in high dose group, with no changes in the anogenital distance. Neonatal M from this group presented reduced seminiferous tubule area, reduced germ cell population as well as reduced Sertoli cells per seminiferous tubule. Examination of Sertoli cell microtubule cytoskeleton showed that the microtubule amount per seminiferous tubule was also reduced at 150 ng/mL PND56: no significant alterations in body weight, testis weight and serum testosterone level, but sperm count in cauda epididymis was significantly decreased in the high‐dose group, with no significant changes in sperm morphology. Testes in both dosed groups displayed a smaller seminiferous tubule area. In the two dose groups, the percentage of stage VIII seminiferous tubules was also significantly reduced in a dose‐dependent manner. A few immature germ cells improperly appeared in the lumen. Immature germ cells were also found in the cauda epididymis in the high dose group. There were significant decreases in the number of spermatocytes and spermatids per seminiferous tubule in the high‐dose group. Microtubule damage was still remarkable in adult testes; microtubule tracks in stages VI − VII tubules became shorter and thinner in a dose‐dependent manner. Microtubule cytoskeleton in Sertoli cells is a sensitive target of TBBPA‐bDiBPrE implying the impairment of the blood‐testis barrier integrity	No NOAEL/LOAEL identified a
Li, Xiong, Chen, et al. (2023). Extended exposure to tetrabromobisphenol A‐bis(2,3‐dibromopropyl ether) leads to subfertility in male mice at the late reproductive age	Purity: > 98% MREDA (NR)	CD‐1 mice 15 dams (10 M pups/dam) Age: 0–8 months PND7: 3 pups/group PND21: weaning PND21‐8 months: 1 M pup/5 litters/group	Oral (drinking water) 0, 150, 3000 ng/mL (expected doses: 0, 50, 1000 μg/kg bw per day) Solvent: DMSO Duration: PND0‐8 months In addition, male mice exposed from PND0 up to 8‐month age were allowed to mate with non‐treated females for the evaluation of fertility	At 8 months: body weight, anogenital distance and serum testosterone levels were not significantly altered Testis weight showed a non‐statistically significant decreasing trend. Reduced epididymal sperm count was observed in the high‐dose group Morphologically abnormal spermatozoa (amorphous head, no hook, folded neck and curly or bent tails) increased with increased doses. The percentage of stages VII‐VIII seminiferous tubules was significantly reduced even in the low‐dose group. The testes of treated mice showed reduced seminiferous epithelium height and seminiferous area in stages VII–VIII seminiferous tubules. Immature germ cells improperly appeared in the lumen in the treated groups and cell debris was also observed in the epididymis, particularly in the caput epididymidis There were decreases in the numbers of spermatogenic cells at different developmental stages. Fewer Sertoli cells were observed per seminiferous tubule in treated testes. Moreover, microtubule of Sertoli cells became shorter and thinner following long‐term exposure with a dose‐dependent decrease. High‐dose treated mice had fewer offspring with a female‐biased sex ratio	No NOAEL/LOAEL identified a

Abbreviations: F, females; GD, gestational day; LOAEL, lowest‐observed‐adverse‐effects level; M, males; NOAEL, no‐observed‐adverse‐effect level; NR, not reported; PND, postnatal day.

^a The CONTAM Panel considered that there is a high level of uncertainty regarding the concentrations of TBBPA in the drinking water and the doses calculated from these concentrations, and thus, no NOAEL/LOAEL was identified from this study.