Gas oils, paraffinic

Endpoint summary

Description of key information

Acute Oral Toxicity:
The acute oral LD50 for other gas oils is > 5000 mg/kg of bodyweight in male and female rats, based on no mortality and minimal signs of toxicity (OECD 401).
Acute Inhalation Toxicity:
The acute inhalation LC50 for other gas oils for both male and female rats is 4.6 mg/L (aerosol) (OECD 403). This is supported by a read-across study from straight-run gas oils, which shows an LC50 of 1.78 mg/L (aerosol) that is applicable to other gas oils as a conservative LC50. 
Acute Dermal Toxicity:
The acute dermal LD50 for other gas oils is > 2000mg/kg body weight for male and female rabbits, based on no mortality or evidence of adverse effects (OECD 402).

Additional information

Acute Oral Toxicity:

The key acute oral toxicity studies investigated the effects of hydrodesulfurised middle distillate (Klimisch scores = 2, API 1982a,b). In both studies, fasted Sprague Dawley rats (5 male/5 female) were administered a single oral dose of >5000 mg/kg body weight via gavage. After 14 days of observation, no mortality or abnormal changes in body weight were observed in any of the rats. At necropsy, two mildly enlarged cervical lymph nodes, a distended stomach, moderately dilated renal pelvis, and alopecia on the stomach area and red exudate and severe corneal ulcerations in the eyes were found. The acute oral LD50 for both studies was > 5000 mg/kg body weight. 

  

Acute Inhalation Toxicity

For acute inhalation toxicity, the key study investigated the effects of hydrodesulfurised middle distillate in male and female Sprague Dawley rats exposed (whole body) to aerosol concentrations in the range of 0-7.3 mg/L for 4 hours (Klimisch score = 2, API 1983a). There were no reported mortalities during the exposure period, and macroscopic and microscopic findings were limited to the lungs, where moderate to severe pulmonary irritation was apparent. Based on these results the LC50 for both males and females is 4.6 mg/L (aerosol) for other gas oils.

In an additional key read-across acute inhalation toxicity study (API, 1987a), groups of young adult Sprague-Dawley rats, 5 male and 5 female in each exposure group, were exposed by inhalation route to a straight run middle distillate (petroleum) aerosol for four hours to the whole body at concentrations from 1.05 mg/L to 5.39 mg/L. Animals were observed for 14 days. No animals died in the air-only control group or the lowest test material concentration, while all the animals exposed to the highest concentration had died by two days post-exposure. Body weight gain depression, pharmacotoxic signs, gross necropsy findings and acute histopathologic changes in the lung were all considered related to treatment. They were most severe in the animals that died 2 to 4 days after exposure. Estimated LC50 values were 1.78 mg/L for the combined sexes and 1.72 mg/L for males rats and 1.82 mg/L for females.

 

Additional data exist on the acute inhalation of other gas oils (API, 1983). This information on a hydrodesulfurised middle distillate aerosol is presented in the dossier. It had an LC50 of 7.64 mg/L, which is higher than the limit for classification.

 

Acute Dermal Toxicity

The key acute dermal toxicity studies investigated the effects of hydrodesulfurised middle distillate at a dose of 2000 mg/kg body weight for 24 hours on male and female rabbits (Klimisch scores = 1, API 1982a,b). Animals were observed for 14 days post-exposure. Neither study reported mortality in the animals, and only slight skin irritation. Based on results, the LD50 for other gas oils is >2000 mg/kg body weight.

Justification for classification or non-classification

Other Gas Oils are not classified for acute oral or dermal toxicity based on the LD50 values, which are greater than the criteria for classification defined in the EU CLP Regulation (EC No. 1272/2008). 

 

Other Gas Oils are classified as harmful by inhalation (H332) based on an LC50 of 1.78 mg/L (aerosol) for male and female rats seen with straight-run gas oils, according to the EU CLP Regulation (EC No. 1272/2008).

 

Regulatory classification and labelling for aspiration toxicity relies on the measured or calculated kinematic viscosity of a substance at 40°C rather than results from toxicological studies with animals. Hydrocarbons with kinematic viscosities ≤20.5 mms/sec are classified for aspiration toxicity (H304) according to EU CLP criteria. As members of this category exist as low viscosity liquids that meet these criteria, substances in this category are classified for aspiration hazard. Other Gas Oils are classified as aspiration hazards (H304).