SONOMA COUNTY -- A proposed rock quarry that proponents say could fill a vital need for gravel for local projects has faced numerous environmental hurdles, chief among them the environmental impact review process after the land off Roblar Road was found to be housing an endangered species.

The county Planning Commission in April had recommended the project to the Board of Supervisors for final approval, but the finding triggered a revised EIR.

While some cite the economic benefit of the 65-acre quarry, environmentalists and nearby residents have criticized the scope of the project, which was approved by the county Planning Commission but faced further review after larvae of the endangered California tiger salamander was discovered.

The approval of the quarry could still occur sometime in mid-September, pending the feedback the county received from the public, for which the period ended last Friday, and pending the outcome of the revised EIR that took into account both the endangered salamander as well as new guidelines on greenhouse gas emissions by the Bay Area Air Quality Management District, according to Scott Briggs, environmental review manager for the county Permit and Resource Management Department. It wasn’t required of the county or the applicant to do so, but it was done regardless.

“We decided we’re going to have to re-circulate the EIR anyway, so we also added a whole discussion on greenhouse gases,” Mr. Briggs said of the new guidelines, adding that the applicant, North Bay Construction, was willing to use the new standards that stipulate any new project must emit fewer than 1,100 metric tons of greenhouse gas emissions for a development project to be deemed less than significant. The new guidelines went into effect June 2.

Mr. Briggs said the new guidelines from the Air Quality Management District didn’t require the EIR to be revamped because projects already under way or in the approval stages before the June 2 guidelines did not need to meet the new requirements. The discovery of the larvae, however, did require a new EIR. But given the timing, and as a means of being more environmentally thorough, county planning staff and the applicant opted to include the new greenhouse emissions standards -- spurred by the California Environmental Quality Act -- into the new EIR.

The site of the quarry, first proposed seven years ago, has drawn protests from residents concerned about increased truck traffic going to and from the quarry and fearing that digging for gravel could release toxins into the air while potentially contaminating nearby groundwater.

Critics include the Citizens Advocating for Roblar Rural Quality/Citizens Against Roblar Rock Quarry, which takes issue with an EIR from December 2009 and the planning commission’s April 1 approval of the original plan. They note the proposed site is adjacent to a former landfill and have cited concern about toxic materials such as lead and asbestos becoming airborne during digging.

Proponents, meanwhile, cite the economic benefit, saying the quarry could produce as much as 11 million cubic yards of rock suitable for construction throughout the county, worth roughly $60 million over the course of 20 years.

John Bly, vice president of Northern California Engineering Contractors Association, started a letter-writing campaign urging the quarry’s passage.

He said the county is in need of the gravel, and stopping the quarry will mean lost jobs. He also said the county would have to obtain such materials elsewhere, which would have its own set of environmental and air quality issues.

“It’s just been a struggle to get enough rock to take care of the increased demand,” he said. “The timing is critical with the projects along the [Highway] 101 corridor, and there are more projects down the road.  You don’t want to truck up rock from San Rafael or somewhere else – that creates greenhouse gas emissions too.”

The EIR will face further discussion with Planning Commission hearings this month and will then be forwarded to the Board of Supervisors, which will decide whether to approve the final plan.