SACRAMENTO - Beginning January 1, 1992, the California Air Resources Board's (ARB) Phase 1 gasoline regulations required only lead-free grades to be sold.

But some "lead-free" grades still have high levels of sulfur, phosphorus and manganese and must continue to be pumped from large diameter (15/16 in. Outside Diameter ( O.D.)) nozzles to prevent damage to catalytic converters.

The ARB has issued an advisory to all service station operators, warning that the large diameter nozzles cannot be removed from previously "leaded" pumps (mainly mid-range 89 octanes) because the gasoline will not meet all the ARB specifications for unleaded gasoline until 1994.

The ARB's Phase 1 reformulation standard require all grades of gasoline to meet reduced, summertime vapor pressure standards and the use of detergent additives. In addition, a ban on the use of lead applies to all previously "unleaded" grades.

For the next two years, however, previously "leaded regular" grades of gasoline are not required to meet a 300 parts per million sulfur level and are allowed to continue use of phosphorus and manganese, as well as trace amounts of lead, making them unusable to catalyst-equipped cars.

The dual specifications end on January 1, 1994, when the ARB's standards require that all grades meet "unleaded" specifications, allowing all gasolines to be pumped through the smaller 13/16 in. O.D. nozzle and used in all cars.

Beginning in 1996, the ARB standards require further reformulation to eight specifications of gasoline, producing both winter and summer-time anti-pollution blends.