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Administrative data

Description of key information

A reliable acute oral toxicity study according OECD 401 was conducted in 5 Wistar rats/sex at doses of 3160, 3980, 4495 and 5010 mg/kg bw 4-(1,1,3,3-tetramethylbutyl)phenol in paraffin (Sasol, 1984). A second OECD 401 study was conducted in 5 SD rats/sex at a limit dose of 2000 mg/kg in arachis oil (Safepharm Laboratories 1991). In addition a poorly documented study from Rohm & Haas (1973) reports the oral exposure of 6 albino rats/sex to a limit dose of 5g/kg bw.
In a poorly documented inhalation study 6 albino rabbits were exposed to 116 mg/l octylphenol in isopropyl myristate (Rohm & Haas, 1973). The same study investigated acute dermal toxicity using 6 rabbits (3 intact and 3 abraded). Octylphenol was administered at a limit dose of 2.0 g/kg bw. Dermal toxicity was also assessed in an OECD 402 study (BASF 1981) at doses of 1000 and 2000 mg/kg.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
4 040 mg/kg bw

Additional information

Both OECD 401 guideline studies report a LD50 above 2000 mg/kg bw. From the non-limit dose study a LD50 (rat) of 4040 (3640-4484) mg/kg bw was derived. A poorly documented Rhom&Haas study reports a LD100 of 5000 mg/kg bw.

In an acute inhalation toxicity study, a group of 6 adult albino rats were exposed by inhalation to p-octylphenol (89%) in isopropyl myristate for 1 hour at a concentration of 116 mg/L.  All 6 animals died on day 1. The concentration was too high to derive an LD50. For classification purposes a limit dose of 20 mg/l would be used to determine toxicity by inhalation.


Dermal toxicity was assessed in an OECD 402 study (BASF, 1981). The dermal application of 2000 mg/kg bw for 24 h to 3 rabbits/sex did not cause mortality and no internal abnormalities within a 7 day observation period. This finding was confirmed by a similar study (Rhom&Haas, 1973).

Justification for classification or non-classification

No symbol and risk phrase are required according to EEC labelling regulations - based on a low acute toxicity by ingestion (LD50 > 2000 mg/kg), and for dermal exposure (LD50 > 2000 mg/kg).