NAGS HEAD, North Carolina - Energy companies will soon start looking for oil and gas off the East Coast of the United States. It will be the first time in 30 years. They will start as early as next spring.

The companies use air guns called seismic cannons. They look for oil and gas and are as loud as cannons. They send out blasts every 10 seconds or so. The tests last for weeks at a time.

The guns shoot out sound waves. The waves bounce off rocks and can be studied to make three-dimensional maps. These 3-D maps show where in the rocks under the sea there could be oil and gas.

Government officials and oil companies say these tests are harmless. Bob Edwards disagrees. He is the mayor of Nags Head, a town in North Carolina's Outer Banks. Edwards is worried about what the loud sounds can do to dolphins and whales. The North Atlantic right whale is endangered. Only about 500 are left.

In addition, many sea animals use sound to find food and mates. They also use it to keep track of their young.

People Do Not Agree On Blasting

The government agreed to open an area of the Atlantic Coast from Delaware to Florida for the testing. It said there is no evidence testing harms sea animals.

Leaders in North Carolina, South Carolina and Virginia want to see how much oil and natural gas lies off the East Coast. They hope that President Barack Obama will allow drilling. They say oil drilling will bring jobs and money to the area.

In coastal towns, not everyone is happy about the idea of drilling for oil.

Nags Head gets much of its money from visitors. The tourists rent homes there for vacations. They relax on its beaches.

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

Allen Burrus is a grocer in the town of Hatteras, North Carolina. He said drilling would bring money to the Outer Banks. He does not think the animals will be harmed.

Limits On Cannon Blasting

Government officials say they will put limits on when the cannons are fired. There will be limits on testing during whale migration periods. The companies must also have people on the boats looking out for whales. They must stop testing when animals are too close, the officials said.

The tests "should not cause any deaths" if these steps are taken, they said. In addition, they should not hurt animals' hearing.

A group of oil companies said the government is putting too many limits on the tests. It said the seismic blasts are safe.

Many Unanswered Questions

George Ioup is a professor who has studied the effects of the blasts in the Gulf of Mexico. He said there are many unanswered questions. In the Gulf, whales and dolphins tend to hear and communicate at higher sound frequencies than the sound waves from the cannons.

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

It is different in the Atlantic, he said. Some Atlantic whales operate at low frequencies. They will hear the cannons. Companies have to be very careful near spawning or feeding areas of those whales, Ioup said.