INTRODUCTION A proposed Environmental Protection Agency (EPA) regulation requiring general availability of lead-free@ phosphorus-free gasoline by July 1@ 1974 was published in the February 23@ 1972 issue of the Federal Register. The term lead-free@ phosphorus-free was later defined in the January 10@ 1973 issue of the Federal Register as a motor gasoline of at least 91 research octane number@ that contains not more than 0.05 grams of lead and 0.005 grams of phosphorus per gallon. No sulfur limitations were set@ but comments were solicited. While the proposed lead restriction is higher than the limit of 0.02 to 0.03 grams per gallon suggested by some automobile companies and exhaust control catalyst manufacturers@ it is significantly lower than the 0.07 grams/gallon maximum allowed for unleaded gasoline as defined by the American Society for Testing and Materials (ASTM) which is used as a guide by oil companies. Because of the expressed interest in the allowable trace lead content for unleaded gasoline@ the API Committee on Environmental Affairs@ in March 1972@ requested its Engine Fuels Subcommittee to carry out a voluntary intra-industry survey to obtain all available information on the actual level of trace lead in gasolines being marketed as unleaded in the United States. The Engine Fuels Subcommittee assigned this project to its Interdivisional Task Force on Trace Elements@ designated EF-15.
API PUBL 4179-1973 history
1973API PUBL 4179-1973 TRACE LEAD CONTENT OF UNLEADED GASOLINES CURRENT STATUS AND FUTURE PROPOSALS