The company that wants to turn sea water off Carlsbad into drinking water said last week that it hopes to clear up questions about how it will minimize harm to fish and offset greenhouse gas emissions by April or May.

Poseidon Resources Inc. received conditional approval in November to build a desalination plant from the California Coastal Commission, the key environmental watchdog that must approve the project.

But commissioners said they needed more specific details about the environmental harm the project could cause and how it could be eased.

Meanwhile, Coastal Commission staff members who recommended the commission reject the project said they were working with Poseidon to clear up the final environmental questions.

And environmental foes said they may file lawsuits against Poseidon and the Coastal Commission to block the plan.

Peter MacLaggan, vice president of Poseidon Resources, said last week that the company believes it will finalize its coastal permit and have a plant pumping out "drought-proof" drinking water in the near future.

"The important thing is that we remain on track to get under construction by 2008 and provide water … by the end of 2010," he said.

Since 2000, Poseidon has been studying the idea of building an estimated $300 million plant at the Encina Power Station in Carlsbad that could turn 50 million gallons of sea water a day into drinking water.

Conditional approval

On Nov. 15, coastal commissioners essentially granted the project the permit that could push it toward construction.

But it was a less than unanimous decision, and one that environmental opponents said was flawed.

After a sometimes-tense debate, opposition from commission staff, and accusations that Poseidon had withheld important environmental information, commissioners ended a marathon, nine-hour hearing by voting 9-3 to approve the permit.

But commissioners also said Poseidon had not done enough to answer environmental-harm questions.

They said before Poseidon could start building, the company had to provide the commission specific information about how the plant would minimize killing fish and marine life, and offset the carbon gases it would create.

The commission's staff said Poseidon offered only summaries of studies, not the supporting evidence to substantiate the company's plans to lessen environmental harm.

"We can't determine mitigation if we don't see their studies," said Coastal Commission Executive Director Peter Douglas after the meeting. "We need to understand what the dimensions of the impacts are so we can craft mitigation plans."

MacLaggan and Poseidon say they submitted extensive environmental studies.

The company said in its written material and at the hearing that its research determined that the plant would kill about 2 1/2 pounds of fish per day and a less than significant amount of phytoplankton, fish larvae and other microscopic organisms.

Poseidon offered to offset the marine-life harm by creating 37 acres of new wetland habitat in a joint San Dieguito River Valley program.

MacLaggan said last week that Poseidon provided the commission with more information about its fish studies since the meeting. He said the company and commission staff were starting to work together on remaining questions.

Challenges coming?

Poseidon's project may also have to contend with legal challenges to its permit.

Environmental groups that continue to oppose the project said the commission's conditional approval was illegal.

Marco Gonzalez, an environmental lawyer active in the Surfrider Foundation, said the commission staff's assertion that Poseidon hadn't submitted enough information made it impossible to award a conditional permit.

The Coastal Commission's lawyer appeared to agree with that assessment at the Nov. 15 hearing, but commissioners ignored that opinion.

"I'd say there's a fairly strong chance (the commission and Poseidon) are going to be sued," Gonzalez said. "That's as much as I can say. Even they recognize there is exposure based on the confusing way the project was approved."