10. PREVENTION OF HAZARDS FROM CHRONIC TOXICITY OF COSMETICS 325 should be decided by the responsible scientific investigator: nevertheless, some guiding principles as set out in this Report that take account of the uses to which the cosmetic will be put, should be considered. Cosmetic preparations, in general, are intended for adults, but there are some special preparations for children. Preparations for adults may also be used by children either accidentally or intentionally. Infants and children must be given special protection against toxic hazards. The possibility should be explored of establishing more effective human epidemiological studies in the field of chronic toxicity hazards that may attend the use of cosmetics. I)IFFERENT COSMETIC INGREDIENTS Some constituents of toilet preparations were considered in the light of the general principles. The lists of materials are not considered to be com- prehensive. Preservatives and antioxidants The maintenance of a high level of cleanliness and hygiene in factories and other premises devoted to the manufacture of cosmetic preparations such as shampoos, creams, emulsions and toothpaste, is of the utmost importance. Completely aseptic conditions of handling are seldom attain- able, so preservatives may have to be added to the final product. In addi- tion, antioxidants are required to prevent oxidative changes in particular ingredients. In order to prevent contamination and deterioration of creams and emulsions, these are best supplied in completely filled tubes (metal or plastic) in which they are more protected than they are in open jars or bottles. Category C Preservatives: (i) Benzoic acid (0.2 to 0.3%) is effective in toothpaste below pH 6.0. At higher pH values glycerol (at least 50% of the aqueous phase) is suitable. (ii) Esters of p-hydroxybenzoic acid up to 1.5ø/0 are acceptable they are, however, relatively inefficient, particularly in preparations with pit above 7.0. Antioxidants: Tocopherol, ascorbic acid and isoascorbic acid are accept- able, as are butyl hydroxyanisole, butyl hydroxytoluene, and gallates in limited concentration.

326 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Category C.-Ext. (i) Chlorinated phenols in concentrations of about 0-25% are said to be effective, but there is doubt about their safety. (ii) Formaldehyde in concentrations up to 0.05% is effective and accept- able. Some other compounds, e.g. paraformaldehyde and 1-hydroxymethyl- 5-5'-dimethylhydantoin which liberate formaldehyde might also be con- sidered. The permitted content for each compound must be controlled so that the amount of free formaldehyde evolved does not exceed 0.05%. Category C.-W.R. Phenylmercuric salts are tolerated only in shampoos within certain concentration limits, and the label should include instructions to rinse carefully. Colours At present the only colours completely acceptable in Category C are the approved food colours, but many others used in lipsticks must be provision- ally accepted. These further colours, which are said to be indispensable to give the range of colours required, should be tested biologically within 5 years. For dental products (including toothpastes) the food colours and, on a provisional basis, Rose Helindone (CI 73360) and Alizarin (CI 58000), only should be allowed. In certain instances, e.g. fluorescein derivatives, limitations must be placed on the use, or on the proportions used. For Categories C.-Ext. and C.-W.R. no positive lists are required and negative lists only are recommended. Manufacturers will thus use on their own responsibility any colours available for these purposes, except the colours designated in the negative list. Surface active agents Surface active agents are long chain amphiphilic derivatives which alter interfacial tension, and include artionic agents used for cleansing and as emulsifiers, non-ionic and amphoteric agents used mainly as emulsifiers in creams and lotions, and cationic agents which are anti-bacterial. Chronic biological tests using both oral administration and skin applica- tion, conducted with the major anionic surfactants, among which are soaps, alkyl sulphates, alkyl benzene sulphonates, alkyl glyceryl ether sulphonates, lauryl trioxyethylene sulphate and alkyl benzene ether sulphonates, have