Pyrocatechol

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Remarks:

Only 6 female rats were tested instead of 5 males and 5 female rats. Purity is unspecified.

Data source

Reference

Reference Type:

publication

Title:

The benzenediols: catechol, resorcinol and hydroquinone: a review of the industrial toxicology and current industrial exposure limits.

Author:

Flickinger C.W.

Year:

1976

Bibliographic source:

American Industrial Hygiene Association Journal, 37(10), 596-606.

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: Federal register (see below)

Deviations:

not specified

Principles of method if other than guideline:

Federal Register (1961) pp.7333-7341, Part 191- Hazardous Substances: Definitions and Procedural and Interpretative Regulations, Final Order

GLP compliance:

no

Test type:

other: inhalation study

Test material

Test material information

Constituent 1

Reference substance name:

Pyrocatechol

EC Number:

204-427-5

EC Name:

Pyrocatechol

Cas Number:

120-80-9

Molecular formula:

C6H6O2

IUPAC Name:

pyrocatechol

Details on test material:

Aldrich Chemical Company, Inc Catechol, Catalog N° 13. Purity unknown.

Test animals

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan, no more data
- Age at study initiation: no data
- Weight at study initiation: 87 to 126 grams
No more data

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

not specified

Vehicle:

other:

Details on inhalation exposure:

- Aerosol generation system: 
Samples were dissolved in distilled water and the resulting solutions were aerosolised using a D18 Dautrebande aerosol generator operated at 30 psi. At this operating pressure, the D18 generator delivers droplet diameters of 1 µ size and smaller. Airborne concentrations were determined by measurement of the volume loss of solution following aerosolisation. 
The weight of sample present in that volume was then calculated and related to the total volume of air used in generating the aerosol to obtain chamber concentrations. The nominal airborne concentrations of sample were 1500, 2000 and 2800 mg/m3.

Analytical verification of test atmosphere concentrations:

not specified

Duration of exposure:

8 h

Concentrations:

1.5, 2.0 and 2.8 mg/l (nominal)

No. of animals per sex per dose:

6 females per dose

Control animals:

not specified

Details on study design:

Animals were held for 14 days following exposure and were then weighed and sacrificed for gross necropsy.
Rats were observed during a 14-day post-exposure period.

Results and discussion

Effect levels

Key result

Sex:

female

Dose descriptor:

LC0

Effect level:

>= 2.8 mg/L air

Exp. duration:

8 h

Mortality:

No deaths resulted when rats inhaled catechol-water aerosols at 1500, 2000 and 2800 mg/m3. 

Clinical signs:

other: Signs of intoxication are irritation, persisting tremors 24H after exposition. No effects were observed at 1.50 mg/l.

Body weight:

All animals had normal 14-d weight gain

Gross pathology:

No lesion attributable to inhalation of aerosol was seen at gross necropsy. 

Other findings:

Prior to sacrifice at the conclusion of the 14-day holding period, all six rats previously subjected to an aerosol of 2.8 mg/l had blackened toes and tails. Some of the toes of several of these rats were missing, as well as the tips (2 cm and less) of the tails of all six rats. 
Similar tail loss occurred in 2/6 rats subjected to 2.0 mg/l aerosol, while none of the 6 had this condition 14 d after inhaling an aerosol of 1.5 mg/l. The loss of distal portions of the tail and accompanying loss of digits at doses of 2.8 and 2.0 mg/l was dose related. This loss of appendages by absorption of various amount of catechol (including lethal doses) through the intact skin and gastroenteric tract of various animals has not been noted in the literature.
Other toxic signs were reported: tremors within 6 or 7 hours and persisted trough first post-exposure day, and normal in the second post-exposure day.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Since no mortality was observed at the higher tested concentration (2.8 mg/L) Catechol is not classified harmful by inhalation route.

Executive summary:

In a study (Flickinger, 1976), 6 female Wistar rats were exposed to aerolizated solutions of catechol at nominal doses from 1.5, 2 and 2.8 mg/L for 8 hours. The LC0 (8h) was > 2.8 mg/L. At this dose, no mortality occured, but effects were noted on central nervous system and loss of tail and toes.

Based on the LC0 and according to CLP Regulation criteria, catechol is not considered as harmful by inhalation route.