Respiratory response of guinea pigs to oil mists

Respiratory function was measured in guinea pigs exposed for one hour to submicrometer oil mists. Five oils were used: medicinal grade mineral oil, laboratory grade paraffin oil, light lubricating oil, unused motor oil and used motor oil. The last three oils were also studied after having been reacted with sulfur dioxide. No alterations were produced by exposure to any of the oils at concentrations of 10 or 40 mg/m3. At concentrations above 200 mg/m3 both the reacted and unreacted light lubricating oil caused a decrease in compliance which remained throughout the post-exposure period. Although the average flow-resistance of the group was increased by the unreacted unused motor oil and by the reacted used motor oil, the variation in response was too great to make this response statistically significant. The fact that reaction of the oils with sulfur dioxide did not increase irritant action indicates that the reaction products with sulfur dioxide are not acutely irritant.