Gas oils (petroleum), straight-run, high-boiling

Endpoint summary

Description of key information

Key acute oral (OECD 401), dermal (OECD 402), and inhalation (OECD 403) studies were identified for straight run gas oils.  LD50 and LC50 values were as follows:
• The oral LD50 was > 5000 mg/kg bw in male and female rats.
• The dermal LD50 was > 2000 mg/kg bw in male and female rabbits.
• The LC50 was 1.78 mg/L in male and female rats.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

1 780 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Additional information

Key acute oral, dermal, and inhalation studies were identified from American Petroleum Institute (API) (Klimisch scores=1). Based on the results of the studies, straight run gas oils are of low acute toxicity, with an oral LD50 greater than 5000 mg/kg (rat), a dermal LD50 greater than 2000 mg/kg (rabbit), and an inhalation LC50 of 1.78 mg/L (rat). Additional detail on the studies are reported below.

Acute Oral Toxicity

In an acute oral toxicity study (API, 1985a), five male and five female fasted Sprague-Dawley rats were given a single oral dose of straight run middle distillate (petroleum). Clinical signs observed during the study period included hypoactivity, ataxia, diarrhoea, lacrimation, oily yellow-stained coat, and hair loss. No mortality was observed. Body weights in both males and females increased at day 7 and continued to increase at 14 days post-treatment. The oral LD50 for straight run middle distillate in male and female rats was calculated to be greater than 5000 mg/kg body weight.

Acute Dermal Toxicity

In an acute dermal toxicity study (API, 1985a), 4 male and 4 female albino New Zealand rabbits were exposed to straight run middle distillate (petroleum) for 24 hours to approximately 10% of their body surface, at 2000 mg/kg bw. No sign of systemic toxicity or mortality was observed at this dosage level. Slight to moderate dermal irritation for erythema, oedema, atonia, desquamation, and fissuring, and slight coriaceousness was observed. The dermal LD50 was determined to be >2000 mg/kg in males and females.

Acute Inhalation Toxicity

In an acute inhalation toxicity study (API, 1987), 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. Supporting studies on acute oral and dermal toxicity offer further support that straight run gas oils are not acute oral or dermal toxicants, with the reported oral LD50 value being greater than 5000 mg/kg in male and female rats and the dermal LD50 value being greater than 2000 mg/kg in male and female rabbits (ARCO, 1990a, 1990b).

Justification for classification or non-classification

Based on evaluation of all the acute toxicity data discussed above, straight run gas oils do not meet the criteria for classification as an acute oral or dermal toxicant under the EU CLP Regulation (EC No. 1272/2008), because the LD50 values are greater than the limits for classification defined in the legislation. Straight run gas oil aerosols do meet the criteria for classification as an acute inhalation toxicant under the

EU CLP Regulation (EC No. 1272/2008) and are classified as H322.

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 viscosities ≤ 20.5 mm2/sec are classified for aspiration toxicity according to EU CLP criteria. As members of this category may exist as low viscosity liquids that meet these criteria, substances in this category having kinematic viscosities, based on measured or calculated kinematic viscosities, ≤ 20.5 mm2/s at 40^oC meet the EU CLP criteria for aspiration hazard.

Straight run gas oils with kinematic viscosities ≤ 20.5 mms/sec are classified as aspiration hazards (H304) according to the EU CLP Regulation (EC No. 1272/2008).