1,1-dimethylheptanethiol

Endpoint summary

Description of key information

Key skin, eye, and respiratory irritation data are available for 1,1-dimethylheptanethiol. 
Skin Irritation: Not irritating
Eye Irritation: Not irritating
Respiratory Irritation: Not irritating

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin Irritation

In a key dermal irritation study (Rees, 2012; Klimisch score = 1), three New Zealand White rabbits were dermally administered 0.5 mL of 1,1-dimethylheptanethiol. The test material was applied undiluted to the clipped dorso-lumbar region of each animal and covered with semi-occlusive wrap for a period of 4 hours. An additional site was similarly treated with the exception of test substance and acted as a control. All animals were subsequently observed for a period of four days.

 

Very-slight erythema and oedema were apparent at the test site of one animal one hour after bandage removal. The erythema persisted to the 24 hour examination but all test sites were normal 48 hours after bandage removal. The mean 24-, 48-, and 72-hour erythema and oedema scores were 0. No other signs of test-material related clinical toxicity were observed during the study.

 

Based on the lack of effects observed in this study, 1,1-dimethylheptanethiol is not considered to be irritating to the rabbit skin.

Eye Irritation

In a key ocular irritation study (Rees, 2012; Klimisch score = 1), three New Zealand White rabbits were administered a single ocular dose (0.1 mL) of tert-nonanethiol and observed for 72 hours after instillation. The test material was instilled into the right eye by pulling the lower eyelid away from the eye ball to form a cup into which the test substance was dropped. The eyelids were then gently held together for one second before releasing; the left eye remained untreated. The treated eyes were not irrigated or rinsed after instillation.

 

There was no sign of toxicity or ill health in any rabbit during the observation period. Slight discharge was apparent in the treated eye of each animal one hour after instillation and the animals were overtly normal from 24 hours after instillation. Instillation of the test material gave rise to no or practically no initial pain response.

 

Tert-nonanethiol did not produce any ocular irritation in this study.

Respiratory Tract Irritation

In a key respiratory irritation tract study (Pence, 1983; Klimisch score = 2), four male outbred SPF mice were exposed via head-only inhalation to 7.00 mg/L (1067.5 ppm) of 1,1-dimethylheptanethiol for two periods of 1 minute exposures separated by a 10 minute exposure to room air. Animals were then observed for 5 minutes or until the respiratory rate returned to pre-exposure rates.

The test material was applied as a vapour in a head only exposure chamber attached to a plethymograph. One of the four mice demonstrated changes in respiratory rates during the first minute (0 -25% decrease in respiratory rate) and two mice in the second minute (0 -25% decrease in respiratory rate) of exposure to 7.00 mg/L1,1-dimethylheptanethiol. Based on the results the authors concluded that the test material is not an irritant when 7.00 mg/L is inhaled by mice. Compound-induced corrosion was not reported.

Justification for classification or non-classification

1,1-dimethylheptanethiol does not meet the criteria for classification and labelling as a skin irritant as defined by EU Dangerous Substances Directive 67/548/EEC or CLP EU Regulation 1272/2008.

1,1-dimethylheptanethiol does not meet the criteria for classification and labelling as a respiratory irritant as defined by EU Dangerous Substances Directive 67/548/EEC or CLP EU Regulation 1272/2008.

1,1-dimethylheptanethiol does not meet the criteria for classification as an ocular irritant under EU Dangerous Substances Directive 67/548/EEC or CLP EU Regulation 1272/2008.