Slack wax (petroleum)

Endpoint summary

Description of key information

Read-across toxicity studies for acute oral (OECD 401) and dermal (OECD 402) toxicity  were identified for slack waxes (carcinogenic or unknown feed-stock and non-carcinogenic feedstock).  No acute inhalation toxicity studieshave been reported for slack waxes since inhalation exposure is not expected to occur under normal conditions due to the very low vapour pressures of these substances. LD50 values were as follows:

• The oral LD50 was > 5000 mg/kg bw in male and female rats.

• The dermal LD50 was > 2000 or 5000 mg/kg bw in male and female rabbits.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Additional information

Slack waxes are waxes with entrained oils. Since paraffin and hydrocarbon waxes are non-hazardous the category hazard profile is determined by the entrained oils. Since the entrained oils are a minor portion of the slack waxes, this is considered to be a worst-case approach.

Slack waxes (carcinogenic or unknown feed-stock and non-carcinogenic feed-stock) are of low acute toxicity, with acute oral LD₅₀s greater than 5000 mg/kg (rat) and dermal LD₅₀s greater than 2000 (or 5000) mg/kg (rabbit).

Slack Waxes (Carcinogenic or Unknown Feed-stock)

Read across justification

No acute oral or dermal toxicity studies have been reported for slack waxes (carcinogenic or unknown feed-stock), but a study has been reported for unrefined / acid treated lubricant base oils, materials similar to the oil entrained in slack waxes (carcinogenic or unknown feed-stock).

Acute Oral Toxicity:

One key read-across acute oral toxicity study in the rat (API, 1986a) was identified for slack wax (carcinogenic or unknown feed-stock).

In an acute oral toxicity study (API, 1986a) conducted in rats, API 84-01, an unrefined light paraffinic oil (CAS No. 64741-50-0) was administered orally as a single dose (5000 mg/kg undiluted) to 5 male and 5 female Sprague-Dawley rats. The animals were observed for clinical signs and mortality at hourly intervals for the first 6 hours post-dosing and twice daily thereafter. Body weights were recorded prior to fasting, prior to dosing and at 7 and 14 days post-dosing. At 14 days, all surviving animals were killed and subjected to a gross examination. There were no deaths during the study, and growth rates were unaffected by dosing. Clinical signs that occurred during the first 3 days included hypoactivity and diarrhoea. All animals returned to normal by day 14. At gross necropsy, there were no visible lesions. The oral LD₅₀ in this study was greater than 5000 mg/kg.

Acute Inhalation Toxicity:

Inhalation exposures to slack waxes (carcinogenic or unknown feed-stock) are not expected to occur under normal conditions due to the very low vapour pressures of these substances.

Acute Dermal Toxicity:

One key read-across acute dermal toxicity study in the rabbit (API, 1986a) was identified for slack wax (carcinogenic or unknown feed-stock).

An acute dermal toxicity study (API, 1986a) was conducted in rabbits with API 84-01, an unrefined light paraffinic oil (CAS No. 64741-50-0). The undiluted test material was applied as a single dose (2 g/kg) to the shorn, abraded skin of 4 male and 4 female rabbits and the treated site was covered with an occlusive dressing for 24 hours. After removal of the dressing, the skin was wiped with a wet towel to remove residual test material. The rabbits were observed for clinical signs and mortality every hour for the first 6 hours, then daily for dermal irritation and twice daily for clinical signs and mortality. Observation was carried out for a 14-day post-treatment period. Body weights were recorded prior to administration of the test material, again 7 days post-dosing and at study termination (14 days). At termination, all surviving animals were killed and subjected to a gross examination. There were no mortalities during the study and no clinical signs of toxicity except for dermal irritation at the site of application. The dermal LD₅₀ for this study was greater than 2000 mg/kg.

Slack Waxes (Non-carcinogenic Feed-stock)

Read across justification

No acute oral or dermal toxicity studies have been reported for slack waxes (non-carcinogenic feed-stock), but such studies have been reported for refined lubricant base oils, materials similar to the oil entrained in slack waxes (non-carcinogenic feed-stock).

Acute Oral Toxicity:

Two key read-across acute oral toxicity studies in the rat (API, 1982a and IBR, 1976) were identified for slack wax (non-carcinogenic feed-stock)

In an acute oral toxicity test (API, 1982a), the test material API 78 -10 (CAS No. 64742-65-0) was administered orally via gavage to 5 Sprague-Dawley rats per sex at 5000 mg/kg. Rats were observed for toxic signs or mortality prior to exposure and then twice daily through the 14 -day observation period. Body weight determinations were made on the day of exposure (Day 0) and on days 7 and 14 of the observation period. All rats were killed and necropsied on day 14. No mortality was observed in any male or female rats orally administered API 78-10. Besides two rats appearing scruffy on day 1, no other signs of clinical toxicity were observed through the study period. Two female rats exhibited below average body weight gain over the study period. Body weight and weight gain of all other animals appeared normal through the study period. No gross lesions were observed in either male of female rats orally administered API 78-10. Based on the lack of systemic adverse effects observed, the acute oral LD₅₀ for API 78-10 is >5000 mg/kg.

In another key acute oral toxicity study (IBR, 1976), groups of fasted, SFP Wistar rats (5/sex) were given a single oral dose of R 9107 (paraffin wax) in arachis oil at doses of 1000 or 5000 mg/kg bw and observed for 7 days. There were no treatment related clinical signs, necropsy findings or changes in body weight. Based on the lack of systemic toxicity effects and mortality, the oral LD₅₀ was determined to be >5000 mg/kg bw (male and female).

Supporting read-across data from studies conducted in rats (API, 1982b; 1982c; 1982d; Elder, 1984; BIBRA, 1993a; BIBRA, 1993b) indicate that the acute oral LD₅₀ for slack waxes (non-carcinogenic feed-stock) is >5000 mg/kg.

Acute Inhalation Toxicity:

Inhalation exposures to slack waxes (non-carcinogenic feed-stock) are not expected to occur under normal conditions due to the very low vapour pressures of these substances.

Acute Dermal Toxicity:

Two key read-across acute dermal toxicity studies in rabbits (API, 1982a) and rats (BIBRA, 1993c) were identified for slack wax (non-carcinogenic feed-stock).

In an acute dermal toxicity study (API, 1982a), groups of New Zealand white rabbits (2/male and 2/ female) were dermally exposed to lubricant base oil API 78 -10 (CAS# 64742 -65 -0) for 24 hours at doses of 2000 or 5000 mg/kg bw.  Animals then were observed for 14 days.

After 14 days all animals were killed and were subjected to a gross necropsy. There were no mortalities in any of the studies. The only clinical signs were skin irritation and the occurrence of soft stool in some animals, but this latter effect was transient. Skin irritation ranged from slight to severe for erythema and oedema; slight to marked for atonia, desquamation, and fissuring; and from slight to moderate for coriaceousness. The LD₅₀s were greater than the doses that had been applied (i.e.2000 or 5000 mg/kg)

In another key acute dermal toxicity study (BIBRA, 1993c), groups of five male and five female young adult Sprague-Dawley rats were dermally exposed to Paraffin wax for 24 hours to approximately 10% of body surface at a dose of 2000 mg/kg body weight. Animals then were observed for 14 days. The test article caused slight skin irritation reactions in a majority of treated animals which persisted throughout the study. However, a previous study performed at BIBRA (Report No.1091(3)/1/93) demonstrated that SX30 is only a mild irritant and has no corrosive (irreversible) properties when applied to intact rabbit skin for 4 hours. Based on the absence of mortality, minimal clinical observations, standard body weight and weight gain, and necropsy results, the median lethal dose was calculated to be > 2000 mg/kg body weight.

 

In a supporting (CTFA, 1972 and Elder, 1984) acute dermal toxicity test, six albino rabbits were treated with a 50% solution of paraffin wax in petrolatum at a dose of 4 ml/kg in a closed-patch exposure for 24 hours. The test material did not cause any systemic effects, and no abnormalities were observed at necropsy; therefore, the LD₅₀was >3600 mg/kg bw.

Supporting read-across data from studies conducted in rabbits (API, 1982b; 1982c; 1982d) and rats (CTFA, 1972 and Elder, 1984) indicate that the acute dermal LD₅₀ for slack waxes (non-carcinogenic feed-stock) is >5000 mg/kg (rabbit) and >3600 mg/kg (Rat), respectively.

Justification for selection of acute toxicity – oral endpoint

One of 9 available studies.

Justification for selection of acute toxicity – dermal endpoint

One of 7 available studies

Justification for classification or non-classification

Slack waxes (carcinogenic or unknown feed-stock and non-carcinogenic feed-stock) do not meet the criteria for classification as acute oral, inhalation, or dermal toxicants under the EU CLP Regulation (EC No. 1272/2008).