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Administrative data

Description of key information

2-(2H-benzotriazol-2-yl)-p-cresol is of low acute oral toxicity with an LD50 of higher than 10000 mg/kg bw as shown in a valid study performed similar to OECD 423. Acute dermal toxicity is higher than 2000 mg/kg bw as derived from experimental data both the actual substance and a read-across substance. Upon 4h-inhalation exposure to dust at a concentration of 590 ± 72 mg/m3, each two of nine  males and two of nine females were found dead within 24h after exposure. Ethanol was used as vehicle and 72% of the particles had a diameter of less than 7 mcirometer.  As higher concentrations were technically not possible, the LC50 is reported as > 590 mg/m3. 

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
discriminating dose
Value:
10 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
discriminating conc.
Value:
590 mg/m³

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
discriminating dose
Value:
2 000 mg/kg bw

Additional information

The key study for acute oral toxicity (Sachsse 1978) was performed and reported similar to the requirements of OECD testing guideline 423. It was not performed prior to the introduction of GLP. The test item was suspended in PEG 400 and was given by gavage to each five male and five female Tif: RAIf (SPF) rats at doses of 4640, 7750 and 10000 mg/kg bw.

Within 2 hours after treatment the rats in all dosage groups showed sedation, dyspnoea, curved position and ruffled fur. Sedation became more accentuated as the dose was increased. Mortality was only observed at the highest dose group: Each one male was found dead after 48h and 7 days, respectively. The surviving animals recovered within 8 to 10 days. They were submitted at random to a necropsy whenever they died, survivors at the end of the observation period. No gross related organ changes were observed upon necropsy.

For most of the other data, information is limited to LD50values, all of them being higher than 5000 mg/kg bw. One study of these studies was performed in mice (Heller 1957). One study was performed at a contract institute that was known to have falsified study reports (Paa 1976).

 

 

The study for acute dermal toxicity rin rats used 1000 mg/kg bw as a single dose which is lower than the limit dose prescribed in the OECD testing guideline 402, but is otherwise valid in regard to procedure and reporting detail (Thomann 1972). In that study, the substance caused no adverse effects. No indication of dermal toxicity was observed in a poorly documented 5-day screening study using approximately 2000 mg/kg bw/d (Heller 1957b). Testing for acute dermal toxicity may be omitted if a substance was found to be non hazardous upon acute oral dosing at the limit dose. The available experimental data confirms the absence of an acute dermal toxicity hazard.

 

The key study for inhalation toxicity (Sachsse 1973) follows the latest OECD guideline 403 (1981) with some deviations such as a shorter observation period and no reporting for individual animals. It was performed prior to GLP, but is reported in sufficient detail. Nose-only exposure to aerosol was applied and the highest achievable concentration was 590 ± 72 mg/m3. Each nine male and nine female rats for exposed for 4h. A 20% suspension in ethanol was sprayed into the exposure chamber by means of a pressure nozzle. The liquid was injected by a motor-driven syringe at a rate of 60 mL/h into a stream of compressed air (2 atm.) Flowing through a spray nozzle at a rate of 10 L/min. The aerosol mist thus produced was discharged into the exposure chamber and the ethanol evaporated prior to reaching the rats. The particle-size distribution in the aerosol was determined gravimetrically on Selectron-Filters, pore size 0.2 µm and 72% of the material had a particle size of less than 7 µm.

After the 4-hour exposure all rats showed tachypnoea, asynchronisms of the extremities, lateral or ventral position and apathy. Two male and two females died within 24h. All other animals were recovered within 48h. Hemorrhage in the lungs and congested organs were observed in dead animals.  No substance related gross organ changes were seen in animals killed at the end of observation period of 7 days. No individual animal data were provided.

Two other studies are available, but their results are not reliable. The first study was performed at a test laboratory that was known to have falsified reports (Myers 1975) and is therefore not taken into account. The design of the second study (Beliles 1965) appears to follow latest OECD Guideline 403 (1981) with deviations: The test concentration was 163 mg/L; air flow rate was not reported; duration of exposure was 1.2 hours instead of at least 4 hours. Most importantly, the particle size distribution was not reported. 

Justification for classification or non-classification

 Classification, Labeling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008.

As a result the substance is not considered to be classified for acute toxicity under Regulation (EC) No. 1272/2008.