Fuel oil, residues-straight-run gas oils, high-sulfur

Endpoint summary

Description of key information

Heavy Fuel Oil Components are of low intrinsic hazard following acute oral, dermal and inhalation exposure.

-The acute oral LD50 was determined to be 4320 mg/kg bw in female rats and 5270 mg/kg bw in male rats.

- The acute inhalation LC50 was determined to be 4100 mg/m3 in rats.

- The acute dermal LD50 in rabbits was determined to be >2000 mg/kg bw.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

4 320 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

4 100 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Additional information

The acute oral toxicity of Heavy Fuel Oil Components following gavage administration to groups of male and female rats has been assessed in a number of GLP-compliant studies using either a “limit study” or standard (multi-group) LD₅₀ design.

In a key acute oral toxicity study (API, 1982a), the test substance was administered to groups of fasted male and female SD rats (n = 5/sex) at dose levels of 3200 – 7810 mg/kg bw followed by a 14 day observation period. Variable mortality was present at treatment levels of 4000 mg/kg bw and above, with complete mortality in the high dose group. The main clinical signs were hypoactivity, ataxia, prostration, diarrhoea, hair loss and eye opacity but no lesions were visible at scheduled necropsy in survivors. The acute oral LD₅₀ was determined to be 4320 mg/kg bw in females and 5270 mg/kg bw in males.

Data from multiple supporting GLP-compliant studies validates the low oral acute toxicity potential of heavy fuel oil components with LD₅₀'s reported to range from close to 5000 (ARCO, 1992d, e) to >5000 mg/kg bw (ARCO, 1992a-c, f-i; ARCO, 1990a, ARCO, 1989a; ARCO, 1986a,b; Mobil, 1988a,b; 1992a; and API, 1980a-d) in rats.

The acute dermal toxicity of Heavy Fuel Oil Components has been investigated in a number of GLP-compliant “limit studies”.

In a key acute dermal toxicity study (API, 1982a), the test material was administered to clipped skin from groups of male and female NW rabbits (n = 4/sex) at 2000 mg/kg bw followed by a 14 day observation period. The test site from 2 animals per sex was lightly abraded prior to dosing. There were no clinical signs or evidence of systemic toxicity, and all animals gained weight during the post-treatment period. No lesions were present at scheduled necropsy. The acute dermal LD₅₀ was >2000 mg/kg bw in both sexes.

Data from multiple supporting GLP-compliant studies validates the low acute dermal toxicity potential of heavy fuel oil components with LD₅₀'s reported to be >2000 mg/kg bw (ARCO, 1987b-e; ARCO, 1989b,c; ARCO, 1990b,c; ARCO, 1992j-n; Mobil, 1988c-e, 1992b; and API, 1980a-d).

In a majority of instances in the dermal studies cited above, groups of male and female rabbits were exposed to neat test substance applied to a region of clipped dorsal skin (lightly abraded in some instances) for 24 h, under occlusion. Following removal of wrappings protecting the test site, animals were observed for clinical signs and body weight gain prior to gross necropsy on study day 14. The experimental design used when the test substance was applied to intact clipped skin was therefore generally consistent with that of guideline recommendations, although use of an occlusive covering may have resulted in enhanced dermal uptake relative to the guideline method.

Results are available from four studies that investigated the acute inhalation toxicity of respirable aerosols of Heavy Fuel Oil Components using male and female rats. No mortality was recorded in “limit tests” involving 4 hr exposure to measured concentrations in a range 320 – 3600 mg/m³ (ARCO, 1986c; 1994a,b) while a multi-group investigation (using exposure concentrations of 2100, 3300 and 4800 mg/m³) returned a calculated LC₅₀ of 4100 mg/m³ for males and 4500 mg/m³ for females (ARCO, 1987a).

Justification for selection of acute toxicity – oral endpoint

One of 21 available studies.

Justification for selection of acute toxicity – inhalation endpoint

One of 4 available studies.

Justification for selection of acute toxicity – dermal endpoint

One of 22 available studies.

Justification for classification or non-classification

The acute toxicity of Heavy Fuel Oil Components has been adequately characterised in a large number of GLP-compliant guideline investigations following oral, dermal or inhalation (aerosol) exposure. Based on available data, Heavy Fuel Oils do not meet the criteria for classification as acute oral or dermal toxicants under EU CLP Regulation (EC No. 1272/2008). Heavy Fuel Oils are classified Acute toxicity 4; H332 under the EU CLP Regulation (EC No. 1272/2008).