LBX98

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Justification for type of information:

No data are available for the target substance. Acute oral LD50 values of 121mg/kg bw, 242 mg/kg bw and 207 mg/kg bw are reported for o-, m- and p-cresols, respectively. Acute oral LD50 values of ~980 mg/kg bw are reported for xylenol and ethylphenol. Data therefore demonstrate greater toxicity for the cresols compared to mixed xylenol isomers and mixed ethylphenol isomers, with some evidence that o-cresol is the more toxic of the cresol isomers. Based on the closest structural similarity, read-across using the xylenol study is required for this endpoint. No dermal toxicity data are available for any Category substance; a waiver is appropriate for the target substance for this endpoint based on the proposed classification of the target substance as corrosive. Robust inhalation toxicity data are available for any Category substance; a waiver is appropriate for the target substance for this endpoint based on the proposed classification of the target substance as corrosive. Experimental data for o-, m- and pcresols, 2,4-xylenol and 2,6-xylenol show that classification for skin corrosivity is appropriate. Data for 3,5-xylenol do not indicate that classification for skin irritation or corrosivity are required. Classification for skin corrosivity is therefore proposed for the target substance based on the weight of evidence and following a worst case approach. Experimental data for o-, m- and p-cresols and 3,5-xylenol show severe eye irritation. Classification for severe eye damage is therefore proposed for the target substance based on the weight of evidence. Skin sensitisation studies report negative results for p-cresol and 3,5-xylenol and a positive result for 2,4-xylenol. Classification for skin sensitisation is therefore proposed for the target substance based on the weight of evidence and following a worst-case approach.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Inhalation hazard test: Exposure to an atmosphere enriched with the test substance at ambient temperature

GLP compliance:

no

Test type:

other: inhalation risk test

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 2,4-xylenol and 2,5-xylenol

EC Number:

905-287-4

Cas Number:

1638758-52-7

Molecular formula:

(CH3)2C6H3OH

IUPAC Name:

Reaction mass of 2,4-xylenol and 2,5-xylenol

Test material form:

solid: bulk

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS- Source: Dr. A. Ivanovas, Kisslegg/Allgäu/Germany- Age at study initiation: no data- Weight at study initiation: 115 - 140 g (male, female) - Fasting period before study: 16- Housing: 5 per cage- Diet: ad libitum - Water: ad libitumENVIRONMENTAL CONDITIONS- Air-conditioned room- Temperature (°C): 22 +-1 °C- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

inhalation: gas

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION- Exposure apparatus: Glass tube - Exposure chamber: 150 mm (diameter) x 1000 mm (length)- Method of holding animals in test chamber: in a segment of the inhalation tube - Source and rate of air: micro-filtered pressure air - Method of conditioning air: passed through a layer of 5 cm finely granulated test substance - air rate: 480 L/h (( L/min)- Treatment of exhaust air: exhaust hood- Temperature, humidity, pressure in air chamber: 24 °C

Analytical verification of test atmosphere concentrations:

no

Duration of exposure:

7 h

Concentrations:

no data, test-substance enriched air (24 °C): < saturation concentration (Cs)Cs = ~ 0.13 mg/L (based on a vapour pressure of 0.027 hPa at 25 ° and the molecular mass of 122)

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days- Frequency of observations and weighing: 1x/d- Necropsy of survivors performed: yes- Other examinations performed: clinical signs, body weight

Statistics:

not applicable

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

other: Hazard level at ambient temperature

Effect level:

> 0.07 mg/L air

Exp. duration:

7 d

Remarks on result:

other: estimated air concentration (as gas) based on saturation (~ 1.3 mg/L), assuming 50 % air saturation under test conditions.

Mortality:

none

Clinical signs:

other: no particular observations

Body weight:

normal

Gross pathology:

no particular findings

Applicant's summary and conclusion

Conclusions:

LC >0.07 mg/L following 7 days exposure

Executive summary:

LC >0.07 mg/L following 7 days exposure

The above results are suitable to be used for read across for Reaction mass of 2,4-xylenol and 2,5-xylenol, due to the category being based on structural similarity and comparable physicochemical properties, leading to similar (eco)toxicological properties.