NAGS HEAD, North Carolina - The boom of seismic cannons will soon sound under the Atlantic Ocean as companies look for oil and gas. It will be the first time oil and gas exploration has been allowed off the East Coast in 30 years. It will start as early as next spring.

Government officials and the oil and gas industry say the exploration is harmless. Bob Edwards disagrees. He is the mayor of Nags Head, a coastal town on North Carolina's Outer Banks. Edwards is worried about what the intense sound waves can do to dolphins and endangered North Atlantic right whales. There are only about 500 right whales left.

"I just can't understand how anybody would propose something that's going to be ... endangering whales and dolphins and turtles and fish," he said.

Marine Animals Rely On Sound

The seismic surveys are done with air guns. They blast out sound waves every 10 seconds or so for weeks at a time. The waves bounce off rocks and return. Echoes from the blasts are used to produce three-dimensional maps. The 3-D maps help companies figure out if there is likely to be any oil and gas in the rock formations.

The government approved opening an area of the Atlantic Coast from Delaware to Florida for the blasts. They said there is no scientific evidence that blasts harm marine animals.

Yet even government scientists are worried about what the extreme sound can do to the hearing and communication of whales and other marine life. Many marine animals use sound to find food and mates, and to keep track of their young.

"It's been pretty well documented that seismic surveys have disrupted animal behavior and animal communication," said Danielle Cholewiak, a government scientist.

Political leaders in North Carolina, South Carolina and Virginia pushed President Barack Obama to approve the seismic testing. They want to see how much oil and natural gas lies off the East Coast. They hope that Obama will allow offshore drilling that will bring in jobs and money.

Wildlife Should Be Protected

In towns such as Nags Head, some people support drilling while others do not.

The area gets much of its money from visitors. Tourists rent homes for vacations and relax on the area's beaches.

Paul Manning owns a cafe on the Outer Banks. He said an oil spill would ruin businesses that rely on visitors.

Yet Allen Burrus, a grocer in Hatteras, North Carolina, said offshore drilling would bring money to the Outer Banks. He suspects the environmental fears are being overblown.

Government officials say they will put limits on when the seismic cannons are fired during whale migration. They will also require sound tests to search for marine animals. People on board will keep watch as well. If whales or other animals get too close, the cannons will be stopped.

The American Petroleum Institute represents oil companies. It said the seismic blasts are safe. The government is putting too many limits on the blasts, it said.

Oil companies "already take great care to protect wildlife," the group said in a statement. Science and years of experience prove that there is no danger to marine animal populations, it added.

What The Whales Hear

George Ioup is a professor who has studied the effects of the seismic blasts in the Gulf of Mexico. He said that in the Gulf, whales and dolphins tend to hear and communicate at frequencies far higher than the sound waves from seismic cannons.

"They probably don't even hear them very well," Ioup said.

It is different in the Atlantic, he said. Species of large Atlantic whales operate at low frequencies and will hear the booms. Companies must take a huge amount of care near spawning or feeding grounds of such whales, Ioup said.

In addition, blasts can be heard for more than 2,000 miles underwater, said Doug Nowacek, who is a professor.

"If there's a survey in Virginia you're going to hear it in southern North Carolina, easily," Nowacek said.

He said there has been far too little information collected on the effects of the seismic cannons. He dismissed oil companies' arguments that the booms are harmless.

"I would say show me the evidence that there's no harm," Nowacek said.