Alkanes, C4-5

Neurotoxicity

Description of key information

Data on main components of the Other Petroleum Gases category indicate members of the category show low sub-chronic and chronic toxicity and low potential for neurotoxicity. Inhalation exposure is the most relevant route. No significant exposure-related toxicological or neurotoxicological effects have been observed in inhalation studies up to 90 days duration on the C2-C4 alkanes or a category stream.

Additional information

Repeat dose toxicity data with neurotoxicity assessments are available for the C2-C4 alkanes and one category stream material. Inhalation exposure is the most relevant route.

 

No systemic toxicity (i.e., no affect on survival, haematological or clinical chemistry parameters, food consumption, body weight, organ weight, and histopathology) or neurological effects (as measured by clinical observations, functional observational battery, and motor activity) were observed in 6-week studies to GLP-compliant guidelines in which ethane, propane, isobutane, butane and were administered to rats by inhalation. The NOAEC in all cases were the maximum dose levels tested (16000, 12000, 9000 and 9000 ppm respectively (equivalent to 19678, 21641, 21394 and 21394 mg/m3 respectively).

 

HLS (2009) report an OECD 414 study designed to assess the potential inhalation toxicity of liquefied petroleum gas (LPG, major components propane and propene) when administered via whole-body exposures to rats for 13 weeks. The assessment included routine toxicology parameters as well as detailed evaluations of neurotoxicity parameters. Rats were exposed to 0 (air control), 1000, 5000 or 10000 ppm of LPG, the highest exposure concentration was selected for safety reasons and approximated 50% of the lower explosive limit.

All animals (except one female animal exposed at the 10000 ppm level) survived to termination. There were no exposure-related differences in the test substance exposed animals compared to the air control animals. There were no treatment related effects on functional observational battery, motor activity parameters or neuropathology. The NOAEC was 10000 ppm. 

Justification for classification or non-classification

Members of the Other Petroleum Gases category are flammable gases at room temperature and therefore dermal and oral exposure is unlikely. They have low sub-chronic inhalation toxicity and studies which included evaluation of neurotoxicity parameters indicate low potential for neurotoxicity. Classification under the DPD (Dir 1999/45/EC) or GHS/CLP is not warranted.