San Diego

Water pollution officials said Monday that they will unveil a plan in early April to seek fines against downtown property owners who continue to ignore their requests to help find the source of a giant plume of underground fuel that threatens redevelopment efforts.

State Regional Water Quality Control Board members told their staff to draft a plan, to be disclosed April 7, that would assess civil penalties against a handful of companies that won’t allow underground tests to find out the source or sources of the 450,000 gallons of fuel. The administrative fines could be as much as $1,000 a day for non-compliance.

The fuel is threatening efforts by the Centre City Development Corp. to redevelop parts of downtown. Pamela Hamilton, the CCDC’s executive vice president, urged board members Monday to get tough with unresponsive landowners so the agency can find out whom to charge for cleaning up the plume.