278 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS to exposure to these products. The PAS-staining biopsy material, reported by Bergmann et al. (3) to indicate the presence of hair spray resins, was also found in the control animals (44). Furthermore, hematologic studies of dogs exposed to commercial hair sprays for up to 2 years (44) failed to demon- strate the blood dyscrasias (aplastic anemia, thrombocytopenia, and leuko- penia) reported as being compiled from the AMA Department of Drugs Registry on Adverse Drug Reactions by DeNosaquo (2). Further evidence of the safety of commercial hair sprays has been reported in two separate studies of hairdressers in Great Britain. In the first, John (45) studied 146 hairdressers, both men and women, who used hair sprays for be- tween 3 and 5 years. Radiographic examination of these hairdressers, from 14 different salons, failed to demonstrate any pulmonary abnormalities. In a similar study by McLaughlin et al. (46), an X-ray survey of 505 hairdressers in Great Britain was reported. The hair sprays included both shellac-based sprays and sprays containing polyvinylpyrrolidone (PVP). In all groups a significant number of hairdressers had used the sprays for more than 6 years. No abnormal X-ray appearances, suggesting the presence of pulmonary granulomatosis (thesaurosis), were reported, despite the fact that the ma- jority of particles in both types of hair sprays had a diameter of less than i/x and were thus capable of being inhaled. In a study of the particle sizes of hair sprays manufactured in the United States, at least 50% of the hair spray par- ticles had a diameter of 35 ,/x or greater (47), which is larger than the size that is capable of penetrating the lungs to a significant extent. Further studies by Larson (47) also attest to the safety of commercial hair sprays. In this study, no differences in midexpiratory flow rate, measured spirometrically, were found between users of hair sprays and nonusers, in a controlled population of female college students. While the controversy over the safety of hair sprays continues, the bulk of scientific evidence at present indicates that earlier con- cerns over their safety is unfounded. ToxiciTY OF HOUSEHOLD AEROSOLS Because of the diverse nature of the products in this category, and the large number of users in all age groups, the toxicity of these products is of major interest to both the consumer and the aerosol industry. Other than the toxicity of the ingredients in a specific preparation, some of the factors contributing to the toxicity of the household aerosols include the pattern produced by aerosol spray (5) and the cooling action of the propellants (12). If the spray pattern of a product is not well controlled, partic]es intended for application in one place may well penetrate into the eye or impact on the skin. The im- paction of particles from these products, because of the relatively high pres- sure exerted at release, may cause aerosol particles, that would otherwise be harmless, to penetrate the surface of the skin or the cornea of the eye, thus

CURRENT PERSPECTIVES ON AEROSOL TOXICITY 279 making removal of the material difficult and increasing the likelihood of foreign body tissue reactions (5, 9). Spray keratitis, such as that just de- scribed, has been reported for hair sprays, insecticides, paint sprays, and de- odorants (5, 9). Furthermore, the cooling and drying action of the propellants and/or solvents in a product may aid in the penetration of aerosol particles into the eye (5). Predicting the toxicity of household aerosols in humans, as a result of screening studies in animals, is not easily accomplished. The anatomy and physiology of the respiratory structures in lower animals is different from man (34) also, diseased humans will often respond differently to a product than w,_'11 healtlay laboratory spedes. Another problem is tlae design of a suitable exposure chamber assuming that the environment can contribute to the po- tential hazards of a household aerosol product, there is little equivaleney be- tween the exposure chambers commonly used in the testing laboratories to evaluate the potential toxicity of aerosol products and the actual rooms that humans live in when using such products (34). In general, though, despite the millions of units of household aerosol products consumed each year in this country, few toxic reactions are reported and, of those that are reported, approximately half are probably due to consumer error in following the in- struetions for use printed on tlae package. TOXICITY AND HYPERSENSITIVITY Toxicity is a function of a chemical compound and its reaction with bio- logical tissues and can usually, but not always, be predicted from animal stu- dies. It is the responsibility of the manufacturer of cosmetic and household aerosols to market products with a low order of toxicity in general, this re- sponsibility has been adequately accomplished. Hypersensitivity, or allergic, responses only occur in a small percentage of users of aerosolized products and, in general, cannot be adequately predicted from animal investigation. It is known, however, that persons with certain allergic diseases and/or a heredi- tary tendency towards respiratory and skin diseases may be more likely to elicit allergic reactions to many types of products commonly used in the home, including aerosols. There is little a manufacturer can do to reduce such ad- verse reactions to commercial aerosols, except to use ingredients which have been shown, through years of use or extensive laboratory and clinical testing, to produce a low incidence of hypersensitivity reactions. Other suggestions to reduce the incidence of aerosol-related allergy would be: pooling of reported allergic responses to products and ingredients clinical testing on a wider scale to determine ingredients eausing allergic responses and limited market- ing of new cosmetic or household aerosols, containing new ingredients, until the allergy profile is well established. (Received May 4, 1073)