Demolishing the Phillips 66 Santa Maria Refinery will have only one “significant and unavoidable” environmental impact, according to the final environmental impact report for the project. … The draft environmental impact report analyzed how demolishing the oil refinery and remediating the soil would effect the environment surrounding it. On Thursday, the San Luis Obispo County Planning Commission voted unanimously to certify the report and approve a coastal development permit for the demolition and remediation project. … The Central Coast Regional Water Quality Control Board will set standards for and oversee the remediation efforts. The soil will be cleaned up to an industrial land use standard, while the water must be cleaned to “background level,” which is the state of the water before contamination occurred, county project manager Susan Strachan said.