Reaction mass of 4-tert-butylphenyl diphenyl phosphate and bis(4-tert-butylphenyl) phenyl phosphate and triphenyl phosphate

Endpoint summary

Description of key information

Acute oral toxicity:
2 key studiess: Acute toxic class method, Limit tests (according to EPA 43:163, 37336-37402 (1978), similar to OECD 401,1981): LD50 > 5000 mg/kg bw (male/female rat).
Acute dermal toxicity:
3 key studies: Standard acute method, Limit tests (according to EPA 43:163, 37336-37402 (1978), comparable to OECD 402): LD50 > 2000 mg/kg bw (male/female rabbit).
Acute inhalation toxicity:
1 key study: Standard acute method, Limit test (no guideline followed):  LC50, 6h > 0.4 mg/L air (vaporized sample; male rat).

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

400 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Additional information

The two key studies for acute oral toxicity were chosen as they were performed according to methods similar to OECD guideline 401. In both studies 10 male and 10 female rats; 10 male and 20 female rats, resp., were exposed to 5000 mg/kg bw of the test substance and observed for 14 days. The LD50 (for both male and female rats) was found to be > 5000 mg/kg bw.

Four supporting studies were available. In two of these studies, the LD50 was also > 5000 mg/kg bw (5 male rats, and 10 males and 10 females resp.). In one study, no guideline being followed, the LD50 was > 15800 mg/kg bw (2 male and 3 female rats), and in another supporting study, performed according to methodology comparable to OECD guideline 423, the 14d-LD50 was > 5000 (male rats) and > 4700 mg/kg bw (female rats).

All studies support the conclusion that tBuTPP is not acutely toxic via the oral route.

In the three available key acute dermal toxicity tests of Phosflex 71B, Phosflex 72B, and Fyrquel LT resp., 5 male and 5 female rabbits each were exposed to the test substance for 24 hours and observed for 14 days. The LD50 (for both males and females) was found to be > 2000 mg/kg bw in all 3 key studies.

Three supporting studies were available that were not performed according to methods similar to an OECD guideline. In one study the dermal LD50 (for both 5 males and 5 females) was found to be > 2000 mg/kg bw. In the other two supporting studies (standard acute method; 2 male and 1 female rabbits tested) the LD50 was > 7940 mg/kg bw.

All studies support the conclusion that tBuTPP is not acutely toxic via the dermal route.

One key study concerning acute inhalation toxicity study in rats is available. Six male rats were exposed to Santicizer 154 at a concentration of 0.4 mg/l for 6 hours. Signs of intoxication and mortality were observed during the observation period of 14 days. No toxic signs were found. Viscera appeared normal. No mortality occurred. Under the conditions of this test, the LC50 was found to be > 0.4 mg/l for 6 h. In one available very concise supporting report for acute inhalation toxicity 10 male and 10 female rats were exposed to a fine-particle aerosol of Phosflex 51B for 4 hours at a mean concentration of 3.1 mg/l. The LC50 was found to be > 3.1 mg/l for 4h.

Justification for classification or non-classification

For acute oral toxicity, the LD50 value (for both male and female rats) was found to be > 5000 mg/kg bw in both key studies. Based on this value and the criteria outlined in Annex I of 1272/2008/EC and Annex VI of 67/548/EEC, the substance t-BuTTP does not need to be classified for acute oral toxicity.

For acute dermal toxicity, the LD50 value of > 2000 mg/kg bw was used for classification. Based on this value and the criteria outlined in Annex I of 1272/2008/EC and Annex VI of 67/548/EEC, the substance t-BuTTP does not need to be classified for acute dermal toxicity.

For acute inhalation toxicity, the LC50 value of > 0.4 mg/l for 6 h was used for classification. Based on this value and according to the EU criteria outlined in 67/548/EEC and 1272/2008/EC (CLP/EU-GHS) t-BuTTP does not need to be classified and has no obligatory labelling requirement for inhalation toxicity.