A Superfund cleanup of the Gowanus Canal could cost between $300 and $400 million, EPA official Walter Mugdan revealed for the first time in an interview with the Star.

Mugdan, the director of the EPA's Emergency and Remedial Response Division, said the price tag for the project would probably be closer to $400 million, though he stressed the figure is only an estimate.

The cost and scope of the project would dwarf the city's alternative $175 million proposal to dredge the canal and renovate its flushing station. The Bloomberg Administration, which opposes an EPA Superfund clean up, is pushing hard for its own plan, despite having only $15 million right now to put towards the project.

Though jockeying for control of the canal continues, Mugdan said in discussions with the city it has become clear to the EPA that the plans might not be incompatible, as some originally feared. Equally clear, however, said Mugdan, is that the city's plans alone are not enough to clean the canal, something city officials have acknowledged.

The Superfund listing was specifically requested to address sediment contamination, said Mugdan, while the city's plans would largely focus on water quality improvement in an effort to stem further pollution.

"The dredging that the city has proposed would potentially not touch the heavily contaminated sediments," said Mugdan, who dismissed the city's notion that a comprehensive clean up of the canal could be done for just $175 million. Nonetheless, he continued, a surface dredging of the canal by the city could be a "necessary precursor" to a more thorough EPA follow up.

Put most simply, he said, "The stuff they're intending to remove is on top of the stuff we're trying to remove."

Mugdan outlined a potential scenario where the city would begin its work on the canal while the EPA finishes preliminary remediation studies for the site. By the time the studies (expected to take at the very least two to three years) are completed, Mugdan said, the city would likely have finished its work and the EPA could take over, eliminating any awkward overlap.

"The city's plan is by no means an alternative," said Mugdan. In fact the city and EPA proposals are "completely complimentary," he said, in large measure because they would take on different stages of the canal's clean up.

A city spokesperson, Andrew Brent, confirmed that the city is working to coordinate its clean up effort with the EPA and the state Department of Environmental Conservation (DEC).

"The [city's] planned remediation work would be an important, but only preliminary, part of the cleanup," Brent said in a statement. "It would have to coincide with the comprehensive plan that we're developing with the EPA and DEC."

EPA and city officials negotiating what a large-scale clean up of the canal might look like will have to move fast. The Gowanus will most likely be put on the Superfund list this fall, possibly as early as September, according to Mugdan.

In cases where the EPA is all but certain that a proposed site will make the Superfund list, the agency begins remediation study work even before the site is officially placed on the list.

"If we didn't think we wanted to put it on the list we wouldn't have proposed it," said Mugdan. "We're already starting to do some preparatory work."

This appears to be a clear sign that, with the canal a virtual lock for Superfund status, the debate among stakeholders has shifted to figuring out just how to get the work done, and who might fund it.

Typically, the EPA taxes property owners found responsible for onsite contamination to pay for approximately 70 percent of clean-up costs. Once the site is placed on the Superfund list the EPA can begin to identify potentially responsible parties (PRPs).

The Bloomberg Administration expressed anger over recent comments by the EPA suggesting the city would be forced to help pay for the federal agency's clean-up costs. Mugdan said chances are good the city's share of financial responsibility for the clean up, if any, would be minimal as compared to that of energy companies who have contributed to pollution of the canal since the 1860's.

The EPA has extended the current public comment period on the Superfund status for the Gowanus for an additional 30 days to July 8. Mugdan said it is crucial a consensus be reached on the best way forward by then, because the clean up will be complicated and could take a very long time. "It is not inconceivable that a project of this magnitude could take a decade, or more, to complete," said Mugdan