MARTINEZ -- A public hearing on a propane-and-butane recovery project at the Phillips 66 refinery in Rodeo was continued by Contra Costa County Board of Supervisors this week to May 13.

The hearing, on appeals of the Contra Costa Planning Commission's Nov. 19 approval of the project and on its final environmental impact report, started Jan. 21 and was supposed to continue on Tuesday.

The appellants are the environmental organization Communities for a Better Environment and the law firm of Shute, Mihaly & Weinberger on behalf of the Rodeo Citizens Association.

In separate appeals, the appellants argued the environmental report does not adequately study many of the project's potential impacts and it overstates the baseline amounts of propane and butane currently produced at the refinery. They also warned that Phillips plans to process more and dirtier oil.

Phillips 66, characterizing many of the appellants' objections as speculative and based on incorrect assumptions, asserted the project would reduce emissions of the pollutant sulfur dioxide.

New equipment would enable the refinery to recover propane and butane instead of using it as fuel in its boilers or burning off excesses in a process called flaring, the company argued. It added it does not need to refine heavier crudes to make the project work.

Moreover, Phillips 66 said, there are no restrictions on the kinds of crude the refinery can process now or in the future.

The supervisors had continued the Jan. 21 hearing to April 1 to give the county staff and the refinery more time to address questions raised by the public as well as by several public agencies.

The Bay Area Air Quality Management District asked for more information on toxic air contaminants and an analysis of possible risks to public health. The city of Martinez raised concerns over the storage and transport of oil in railroad cars.

Contact Tom Lochner at 510-262-2760. Follow him at twitter.com/tomlochner