Nevada County District Attorney Cliff Newell joined California Attorney General Kamala Harris in filing a civil lawsuit Wednesday against natural gas companies Phillips 66 and ConocoPhillips for allegedly failing to properly inspect and maintain underground storage tanks at more than 560 gas stations in California. “The state’s hazardous waste laws help protect our residents from contaminated groundwater,” Harris said in a prepared statement. “This lawsuit safeguards public health by ensuring proper maintenance of the tanks that store fuel beneath many California communities.” The suit filed in Alameda Superior Court alleges that since November 2006, employees of the Houston-based multinational corporations …