Respiratory Toxicology of Mineral Oils in Laboratory Animals

Abstract

Early subchronic and chronic inhalation toxicology studies on various petroleum mineral oils and formulated lubricants supported the ACGIH TLV of 5 mg/m(3) for mineral oil mist. Additional subchronic studies with aerosolized mineral base oils and lubricants during the last 15 years demonstrated that exposures to aerosols of mineral base oils (often >100 mg/m(3)) resulted mainly in concentration-related accumulation in the lung of alveolar macrophages laden with oil droplets. Inflammatory cells were observed with higher aerosol concentrations, consistent with the clinical literature from highly exposed workers. These pulmonary changes appeared to be a nonspecific response to the presence of deposited aerosol. Studies on sensory irritation during exposures of lab animals to mineral oils indicate possible effects only with very high aerosol concentrations. Coupled with changes in refining to remove carcinogenic polynuclear aromatic hydrocarbons from mineral oils several decades ago, this information indicates that current aerosols of mineral oils have a profile of low toxicity from acute to long-term exposures. Available information suggests that additives in some formulated products and/or maintenance of mineral-based metalworking fluids may play a much more significant role in potential health effects.

Scientific Opinion on Mineral Oil Hydrocarbons in Food

“…These authors also exposed rats to 100 mg/m 3 of the oil for up to 16 months. Lushbaugh et al (1950, cited in Dalbey andBiles, 2003) exposed groups of rats and mice to motor oil (SAE No. 10) at a concentration of 132 mg/m 3 for 3.5 months and to diesel oil (SGF No.…”

“…No compound-related differences were found between the groups for any of the endpoints investigated. Dalbey and Biles (2003) have summarised published work prior to 1985 on inhalation studies of mineral base oils, i.e. a range of lubricant base oils prepared from naturally occurring crude petroleum oils.…”

“…They varied in carbon number, from > 15 and their boiling points were in the range 300-600 °C. Wagner et al (1964, cited in Dalbey andBiles, 2003) exposed various species to an aerosolised light mineral oil containing 85 % naphthenes and 5 % paraffins, at a concentration in air of 100 mg/m 3 for up to 26 months (Saybolt viscosity = 85 -95, cf viscosity of a light motor oil). No consistent difference in tumour incidence was observed in any of the species studied.…”

“…Groups of 27 CAF 1 /JAX mice were exposed to aerosolised oil at 100 mg/m 3 together with 1 000 ppm acetone, to simulate conditions in acetate fibre production for 12 months. Yevich (1965, cited in Dalbey andBiles, 2003) exposed dogs to 100 mg/m 3 of mineral oil (no further information provided) for up to 26 months. These authors also exposed rats to 100 mg/m 3 of the oil for up to 16 months.…”

“…No consistent difference in tumour incidence was observed in any of the species studied. Stula andKwon (1978, cited in Dalbey andBiles, 2003) studied the effects of inhalational exposure of mice and dogs to a fibre-finish oil with 70% unspecified paraffinic mineral base oil (Saybolt viscosity = ~50 at 38 °C) and other ingredients, including surfactants. Groups of 27 CAF 1 /JAX mice were exposed to aerosolised oil at 100 mg/m 3 together with 1 000 ppm acetone, to simulate conditions in acetate fibre production for 12 months.…”