Cal. Health & Safety Code § 78555

Notwithstanding Section 79650, if the department determines that using an alternative treatment technology to conduct a removal or remedial action at a hazardous substance release site listed pursuant to Section 78760 would be more costly than another available and feasible removal or remedial action method that would also achieve satisfactory results, the department may determine not to attempt to recover from the liable person the incremental costs of the removal or remedial action attributable to the alternative treatment technology.