Extracts (petroleum), heavy paraffinic distillates, solvent-deasphalted

Endpoint summary

Description of key information

Key read-across acute oral, dermal, and inhalation toxicity studies were identified from distillate aromatic extracts and other lubricant base oils (OLBO; IP 346 < 3%)  Results for key studies are as follows:
• The oral LD50 was > 5000 mg/kg bw in male and female rats for DAEs in an acute oral study (similar to OECD 401).
• The oral LD50 was > 5000 mg/kg bw in male and female rats for OLBO (IP 346 < 3%) in an acute oral study (OECD 401).
• The dermal LD50 was > 3000 mg/kg/bw in male and female rabbits for DAEs in an acute dermal study (similar to OECD 402).
• The dermal LD50 was > 5000 mg/kg/bw in male and female rabbits for OLBO (IP 346 < 3%)  in an acute dermal study (OECD 402).
• The inhalation LC50 was > 5 mg/L in male and female rats for DAEs in an acute inhalation study (OECD 403).
• The inhalation LC50 was > 5.53 mg/L in male and female rats for OLBO (IP 346 < 3%) in an acute inhalation study (OECD 403).

Additional information

Treated distillate aromatic extracts (TDAEs) are a further processing of distillate aromatic extracts (DAEs) in an attempt to reduce the amount of 3-7 ring PAC that is present. Since the treatment is mostly a selective reduction of PACs, the data from DAEs can serve as read across where treatment was insufficient and a significant amount of PACs still remain (≥ 3 wt% DMSO extractables as measured by IP-346). Where treatment was sufficient to reduce the 3-7 ring PACs (<3 wt% DMSO extractables as measured by IP-346), the material is most similar to a lubricating base oil and it is this data that should be used for read across. 

Acute oral toxicity:

In a key read-across acute oral toxicity study from DAE, groups of fasted, 7 week old Sprague-Dawley rats (5/sex) were given a single oral dose of undiluted light paraffinic distillate solvent at a dose of 5000 mg/kg body weight (API, 1986a). Animals were observed for 14 days. Clinical signs observed included: hypoactivity, ataxia, red stained face, yellow-stained anal area, diarrhoea, and oily haircoat. All animals had returned to normal within 8 days of test material administration. The oral LD50 was determined to be greater than 5000 mg/kg body weight in males and females.

Additional data support that DAEs are not acute oral toxicants (ARCO, 1973c; ARCO, 1982a; ARCO, 1983b, c, d; ARCO, 1985b; Food and Drug Research Laboratories, 1974b). This information is presented in the dossier.

Many key and supporting studies were available to assess the acute oral toxicity of other lubricant base oils (OLBO). The API 1982a study analyzed the acute oral toxic effects of paraffinic oil (CAS 64742-56-9), a sufficiently refined (IP 346 < 3%) OLBO. In this study, rats were administered a single neat oral dose (5 g/kg) via gavage of the respective OLBO. After 14 days of observation, no mortality or adverse clinical signs of toxicity were seen in either male of female rats. At necropsy, one female rat exhibited cystic masses on the spleen; otherwise, necropsy did not reveal any gross abnormalities in either male or female rats. The acute oral LD₅₀for both studies was >5,000 mg/kg (5 g/kg). Based on this data, paraffinic oil is nontoxic when administered orally.

Supporting data from studies(API 1982b; 1982c; 1982d; 1982e; 1982f; 1982g 1986b; UBTL, 1983a; 1983b; 1983c; 1983d; 1983e; 1983f) conducted in rats demonstrate that other lubricant base oils (IP 346 < 3%) have acute LD₅₀s >5000 mg/kg or >2000 mg/kg (NOTOX, 1994).

 

Acute Inhalation Toxicity:

In a key read-across acute inhalation toxicity study, groups of young adult Sprague Dawley rats (5/sex) were exposed by inhalation route to distillate aromatic extract for 4 hours to whole body at a concentrations of 5.0 mg/L (ARCO, 1983a). Animals then were observed for 14 days. All animals were lethargic during the last 2 hours of exposure. From hour 2 of treatment until the first hour post-exposure, animals kept their eyes partially closed and were lacrimating. One rat displayed red nasal discharge following exposure and red ocular discharge. Another rat exhibited yellow eye discharge during the fourth hour post-exposure and red eye discharge the morning following discharge until the end of the third day post-treatment. These findings are considered related to treatment. Three rats of each sex showed pallor and/or swelling of the kidneys. These findings may be related to treatment. The acute aerosol LC50 of distillate aromatic extract is greater than 5.0 mg/L of air.

Additional data support that DAEs are not acute inhalation toxicants (ARCO, 1983e). This information is presented in the dossier.

Multiple key and supporting studies were available to assess the acute inhalation toxicity of other lubricant base oils. The Exxon Biomedical Sciences, Inc. (1988a) study analyzed the toxic inhalation effects of a solvent extracted paraffinic oil, a sufficiently refined (IP 346 < 3%) OLBO. In this study, five male and five female young adult Sprague- Dawley rats were exposed by inhalation route to MRD-87-102 (a sufficiently refined lubricant base oil; IP 346 <3%) for four hours (whole body) at a concentration of 5.53 mg/L. Animals then were observed for 14 days. No mortality in either the control or exposed group was reported. There were no statistically significant differences in mean body weight between groups. Based on the results of the study, the four hour LC₅₀for MRD-87-102 in rats by inhalation would appear to be greater than 5.53 mg/L.

Numerous acute inhalation studies have been made on other lubricant base oils having viscosities ranging from 10-30 cSt(Exxon Biomedical Sciences Inc., 1988b; 1988c, Mobil Oil Corporation 1984a; 1984b, Bioresearch Laboratories, Ltd., 1984a; 1984b; 1984c; 1984c; 1984d; 1984e; 1984f; 1984g; 1984h, Whitman et al. 1989). The majority of the studies show no or minimal lethality at high doses (> 5 mg/L). Only one sample seems to be more toxic, API 83-12 (which results in LC₅₀= 2.18 mg/L). This sample has higher aromatic content and slightly lower viscosity in comparison to the rest of the samples. Most likely the polycyclic aromatic compounds (PACs) content does not contribute to acute toxicity endpoints. The greater acute inhalation toxicity of this substance is more likely caused by the viscosity (10 cSt). Overall, the weight of evidence suggests that LC₅₀values for this category of other lubricant base oils are greater than 5 mg/L.

Acute Dermal Toxicity:

In a key read-across acute dermal toxicity study, groups of New Zealand White rabbits (8/sex) were dermally exposed to undiluted light paraffinic distillate solvent extract for 24 hours to 10% of total body area at doses of 2000 and 3000 mg/kg bw (API, 1986a). Animals then were observed for 14 days. At the 2000mg/kg bw dosage level: diarrhoea, dyspnoea, hypoactivity, prostration, emaciation, soft stool. At the 3000mg/kg bw dosage level: no signs of systemic toxicity (or mortality). Dermal irritation was observed and ranged from slight to severe for erythema and oedema. The dermal LD50 was determined to be greater than 3000 mg/kg body weight in both males and females.

Additional data support that DAEs are not acute dermal toxicants (ARCO, 1973a; ARCO, 1982d; ARCO, 1984a, b, c; ARCO, 1985a; Food and Drug Research Laboratories, 1974a). This information is presented in the dossier.

Multiple studies were available to assess the acute dermal toxicity of other lubricant base oils. The API 1982a study analyzed the acute dermal toxic effects of solvent dewaxed light paraffinic oil (CAS 64742-56-9), a sufficiently refined (IP 346 < 3%) OLBO, at a dose of 5000 mg/kg bw/day for 24 hours on male and female rabbits. In this study, dermal administration at 5000 mg/kg did not result in any dermal irritation or signs of clinical toxicity. Gross necropsy did not reveal any signs of systemic toxicity at the 5000 mg/kg dose level. Consequently, the dermal LD₅₀was determined to be >5000 mg/kg bw.

Supporting data from studies (API 1982b; 1982c; 1982d; 1982e; 1982f; 1982g; and 1986b) conducted in rabbits have also demonstrated that sufficiently refined other lubricant base oils (IP 346 < 3%) have dermal LD₅₀s of >5000 mg/kg bw.

Justification for classification or non-classification

Based on read-across acute oral, dermal, and inhalation toxicity results from DAEs, TDAEs (IP 346≥ 3 wt%) are not classified under the EU CLP Regulation (EC No. 1272/2008) as an acute toxicant. Additionally, based on the lack of adverse effects in read-across studies from OLBOs (IP 346 < 3%), TDAEs (IP 346< 3 wt%) are not classified under the EU CLP Regulation (EC No. 1272/2008) as acute toxicants.