SACRAMENTO, Calif.- School districts in Los Angeles, Orange County, Riverside and San Bernardino would be limited to purchasing new CNG buses unless they prove that the cost of CNG over diesel would negatively impact their budget, under a proposed rule by the South Coast Air Quality Management District. The ruling flies in the face of CARB's decision to allow $12.5 million of Gov. Gray Davis' $50-million budget for the purchase of OEM low-sulfur "green" diesel school bus engines, and another $12.5 million to retrofit old buses with low-emission diesel technology. CARB allotted the remaining $25 million to the purchase of new natural gas buses.

CARB reversed an earlier proposal that excluded new diesel technology from the spending program and allowed only natural gas buses that cost $25,000 to $30,000 more than their new diesel alternatives were to be subsidized. The Board called its inclusion of clean diesel "an intermediate step in the introduction of lower-emission diesel engine technology," and attributed its decision to recent advances in diesel technology, plus economic benefits.

"Because clean diesel buses are much cheaper than their CNG alternatives, school districts can retire more older buses by replacing them with OEM's using the new diesel technology," noted Jerry Martin, CARB spokesman.

In spite of CARB's position, the SCAQMD believes that "only the purchase of alternative-fueled buses will meet the needs of our district," said Sam Atwood, SCAQMD spokesman.

Under California's school bus allotment program, the individual Air Quality Management Districts will distribute the funds. To be eligible, school districts must apply in April. The SCAQMD plans to adopt its ruling in March. Also under discussion is a proposed study of the toxic equivalencies of CNG Vs diesel. According to Atwood, only regular diesel would be part of the study. In addition, a study of greenhouse gas equivalency levels (of which CNG is suspected of being high in) will not be studied. A hearing at SCAQMD