The EPA has approved a water pollution permit for Newport News Shipbuilding but criticized the state for not doing enough to limit the discharge of the toxic boat paint TBT.

The permit had been in the works since 1991 and was redrafted several times to satisfy new regulations and EPA objections. The final version, approved by the state Water Control Board in late May, is technically sound and will protect human and aquatic life, the EPA said.

But the permit allows too many years to pass before it places specific restrictions on the shipyard's discharge of TBT, or tributyltin, EPA Regional Administrator Michael McCabe said in a letter this week to state regulators.

TBT is used on many commercial ships to keep barnacles, mussels and other marine creatures off the hull but has been found to harm fish, clams and other aquatic life.

The permit limits the shipyard's discharge of TBT to a concentration of 50 parts per trillion, but not until 2000. Until then, the shipyard must monitor for TBT paint whenever it removes it from or applies it to the bottom of a ship, as well as follow certain procedures to minimize the amount of TBT that reaches the James River.

"The four-year delay to achieve compliance with the TBT limit seems excessive," McCabe wrote to the Department of Environmental Quality. Requiring the shipyard to meet the limit in two years instead "would provide an enhanced incentive to achieve a solution to this problem and illustrate a sense of urgency commensurate with sound environmental protection."

That's ludicrous, said Frank Daniel, DEQ's regional director. The 50-part-per-trillion limit is so small that it is now technically impossible to comply with, he said.

The Chesapeake Bay Foundation criticized the permit and was disappointed with the decision. "Procedurally, the natural next step would be a judicial challenge, but in Virginia, citizens can't do that," CBF attorney Roy Hoagland said.