Butyl 3-mercaptopropionate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Materials and methods

Test guideline

Test guideline 1

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

GLP compliance:

yes

Test type:

traditional method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Methyl 3-mercaptopropionate

EC Number:

220-912-4

EC Name:

Methyl 3-mercaptopropionate

Cas Number:

2935-90-2

Molecular formula:

C4H8O2S

IUPAC Name:

methyl 3-sulfanylpropanoate

Details on test material:

IUCLID4 Test substance: as prescribed by 1.1 - 1.4

Test animals

Species:

rat

Strain:

other: Crl:CD(SD)BR

Sex:

male/female

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

head only

Vehicle:

air

Remark on MMAD/GSD:

n.a. for vapour

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

276, 350, 456, 493, and 529 ppm (mean measured), equivalent to 1.35, 1.72, 2.24, 2.42, and 2.60 mg/L, respectively

No. of animals per sex per dose:

60

Control animals:

no

Results and discussion

Effect levels

Effect levels 1

Sex:

male/female

Dose descriptor:

LC50

Effect level:

430 ppm

Exp. duration:

4 h

Effect levels 2

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

2.11 mg/L air (analytical)

Based on:

test mat.

95% CL:

>= 1.89 - <= 2.25

Exp. duration:

4 h

Mortality:

There were 25 deaths (12 males; 13 females) during the exposure period. There were no deaths during the 14-day observation period. The incidence of these deaths was exposure-level related, but there was no evident difference between the sexes. All animals died at the highest level, as shown below:

Measured Mortality Ratio
Conc.(ppm) Males:Females
Control 0/5:0/5
276 0/5:0/5
350 0/5:1/5
456 2/5:3/5
493 5/5:4/5
529 5/5:5/5

Clinical signs:

other: Chromodacryorrhoea was the main sign observed during and immediately following the exposure period in both test and control animals; it was considered to be attributable to the restraint procedure used in exposure. The few clinical signs observed in ani

Body weight:

A small temporary body weight loss in control and test animals was considered to be attributable to the procedure used for animal restraint.

Gross pathology:

There were no gross or histopathological evidence of target organ toxicity to account for the deaths.
The pathology of control and treated rats surviving to termination was unremarkable at necropsy or had minor findings such as uterine distension. Histopathology findings were also minor such as leucocyte foci in lung and liver and were consistent with the expected pattern of background pathology in rats of
this strain and age. There were no gross or histopathological findings suggestive of irreversible or delayed toxicity due to test article administration.

Any other information on results incl. tables

The exposure chamber temperature recorded for the control and treated groups ranged between 21 and 22 °C, and the chamber humidity was between 49 and 82%. The chamber air flow rates were in the range of 5.2 and 12.0 L/min. The oxygen concentration ranged between 20 and 21% for the control and treated animals throughout the study. The mean measured concentrations of MMP were 276, 350, 456, 493, and 529 ppm for the nominal concentrations of 396, 437, 682, 595, and 815 ppm, respectively.

Applicant's summary and conclusion

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

The 4-h Inhalation LC50 of MMP as vapour is 430 ppm (2.11 mg/L).