State environmental regulators have blasted the Navy for drafting an inadequate study of a proposed sonar training range off the coast of North Carolina.

Bill Ross, secretary of the Department of Environment and Natural Resources, said Thursday that the proposed range poses a significant risk to marine life and to North Carolina's coastal resources, and that the Navy's study failed to take "this reality into account."

"We tried to point out what our concerns were and what we saw as areas where information was needed," Ross said in an interview. "What I primarily felt was, the information was inadequate and they reached conclusions on information that was insufficient."

Ross urged the Navy to do a more in-depth supplemental study that offered full and unbiased answers to critical questions such as the consequences for marine life and seabirds, and what steps would be taken to avoid harm.

The comments that the Navy released Thursday were among hundreds from state agencies, scientists, environmentalists and citizens collected as part of an environmental review under way for a proposed undersea training range.

The same day, another federal agency issued its conclusion that military sonar may have played a role in an unusual 2004 whale stranding in Hawaii -- a concern raised in North Carolina in 2005 after whales beached along the Outer Banks.

Site near Jacksonville

A 660-square-mile span of ocean off the North Carolina coast near Jacksonville is the Navy's preferred site for its training range, which would teach sailors and pilots to use sonar to track submarines. The technology uses pulses of sound bounced off submerged objects to pinpoint and track subs. Other sites in contention for the range are off Virginia and Florida.

Federal law requires an environmental review that ensures that decisions are based on an accurate understanding of potential consequences, Ross said.

"The Navy cannot meet that mandate here unless it is prepared to take a much broader, harder look," Ross said.

Jim Brantley, a spokesman for Navy Fleet Forces Command in Norfolk, Va., said it was not surprising that the proposal drew strong reaction.

"Any time you do something that is in somebody's backyard, you can expect critical comments," Brantley said.

The Navy will respond to all substantive comments in the final environmental study, which is expected to be published in late fall, he said.

One of the reviewers, Bill Flournoy, director of the state's conservation incentives program, wrote of the Navy study, "Critical steps seem to be omitted, prematurely dismissed or incompletely described. As a consequence, neither reviewers nor decision makers can have confidence in a finding based upon this draft."

Flournoy noted that the section examining fish at the three sites was "nearly useless" and the section on seabirds "completely inadequate." He said the study did not rigorously compare and contrast alternative sites to allow decision-makers to decide which was the most environmentally acceptable.

Recognizing flaws

The Division of Marine Fisheries said it was greatly concerned about the effect of the range on fishing. It said that offshore fishermen are already constrained by regulations and weather and that further disruption of the fishing grounds probably would have severe economic repercussions.

The Navy has acknowledged that it has not adequately explained its conclusion that sonar is harmless to fish. And it has also acknowledged that sonar could disturb some whales, but it rejects the possibility of deaths.

In other comments, Douglas Nowacek, an oceanographer at Florida State University, said it was better to have sonar exercises at one location than at unknown and unmonitored locations. He said the North Carolina site was a better choice than Florida.

But he said the Navy's conclusion -- that endangered right whales do not frequent the waters of the proposed range off North Carolina -- is unfounded.

Nowacek said the most worrisome conclusion in the study is the Navy's statement that whales could tolerate sounds up to 190 decibels before altering their behavior significantly.

"I believe 190 decibels ... is completely unprecedented and, more importantly, not supported by available data," Nowacek said. He said that he and other researchers had seen strong responses from whales at sound levels far below that.

Eye on Hawaii

Scientists suspect that sonar harms whales, but they do not know exactly why.

Additional evidence was revealed Thursday, when the federal Fisheries Service linked military sonar to an unusual stranding of more than 150 whales in a shallow Hawaiian bay two years ago.

The melon-headed whales, which require deep waters to feed, were discovered early July 3, 2004, in Hanalei Bay on the island of Kaua'i. U.S. and Japanese navy ships participating in the Rim of the Pacific Exercises had used sonar on and off for nine hours the day before.

A flotilla of more than 20 kayaks managed to herd the whales to safer waters July 4. Only one, a young calf, remained. It died.

Navy officials said Thursday that they were reviewing the fisheries report. But the Navy's position is that "it's extremely unlikely" sonar caused the Hawaii stranding, said Lt. William Marks, a spokesman based at the Pentagon.

For one, the stranding began about six hours after the Navy ships stopped using sonar, he said. It's not clear whether the animals, if close to the ships, could have reached the bay en masse by then.

Fisheries officials stressed Thursday that they could not prove sonar caused the trouble. But they found no other obvious explanation -- not dangerous weather, harmful algal blooms, illness or evidence of nearby predators.

"We're not convinced that sonar was the unequivocal or sole cause of the event. It's plausible, if not likely, it was a contributing factor," said Dr. Brandon Southall, director of the fisheries service's acoustics program.

This same agency last month announced that it was unable to determine whether sonar played a role in the stranding of more than 35 whales on North Carolina's Outer Banks in January 2005. U.S. Navy ships had used sonar days before.

It's not certain how the Hawaii findings will influence the National Oceanic and Atmospheric Administration's regulation of sonar use on the range the Navy wants to build off North Carolina.

Underwater geography and marine life differ in this state.