The Sonoma County Board of Supervisors? on-again-off-again stance toward the proposed Dutra asphalt plant along the Petaluma River is on again after a vote Tuesday allowing the company to continue discussions with the county.

Opponents had hoped the county would deny the project in what would have been the final vote after a five-year saga of environmental and public health reports. The debate included passionate campaigns for and against the plant?s construction.

Instead, a letter sent July 13 to supervisors from Dutra?s engineers proposing modifications to the controversial plan convinced a majority of supervisors that discussions were worth pursuing.

?In no way is this an indication that I will support the changes, but I am interested in seeing what the applicant comes back with,? said Supervisor Efren Carrillo, who voted for continuing hearings with Dutra.

Carrillo, who represents west Sonoma County, has been the pivotal vote in the Dutra deliberations.

He supported the project when the board gave preliminary approval on a 4-1 vote in February. But in a straw vote last month, he joined two other supervisors in voting against the project, citing health and environmental concerns.

Dutra officials hope to return to the board with a modified proposal in two to three months.

?We are pleased to have the opportunity to make this project work,? spokeswoman Aimi Dutra said after the meeting. ?We remain committed to providing an aggregate source and asphalt plant to south Sonoma County and the Petaluma area.?

The proposed project across the Petaluma River from Shollenberger Park would include asphalt mixing and aggregate recycling. The San Rafael-based company said it also would preserve 19 acres as wetlands.

The project is opposed by Petaluma city officials and has been a rallying point for environmentalists who have protested its location on the riverfront.

Because the site is zoned for commercial use, approval of supervisors is needed because production of road construction material is an industrial use not allowed under the general plan.

In their letter to the board, Dutra engineers suggested modifying three ?significant components:? reducing hourly production, shortening the smokestacks and eliminating an on-site recycling facility.

On Tuesday, Supervisors Paul Kelly and Mike Kerns, in addition to Carrillo, voted to continue hearings. Supervisors Valerie Brown and Shirley Zane voted to end the company?s application.

Zane said continuing discussions would not be fruitful.

?The site continues to be problematic for all the reasons in the environmental impact report,? she said.

About 200 people attended the mid-afternoonmeeting, most wearing stickers and waving signs declaring their support or opposition to the project.

Because the agenda item was not a hearing, no public comment was permitted.

You can reach Staff Writer Laura Norton at 521-5220 or laura.norton@pressdemocrat.com.