Jul 18, 2014 2 min read

The Obama administration on Friday approved using sonic air cannons to map offshore oil and gas in the Atlantic Ocean by measuring sound reverberating through waters shared by whales and other marine life. Some numbers to help explain it:

• 60 decibels. This is how loud humans normally talk.

• 140 decibels. Even momentary exposure to sound at this level can cause permanent hearing damage in humans.

• 180 decibels. The maximum underwater noise from sonic cannons allowed within 500 meters, mitigating physical damage to marine mammals.

• 2,500 miles. How far away lower levels of noise pollution from the cannons have been recorded by hydrophones.

• 138,000. The minimum number of whales, turtles and other sea creatures that could be harmed, according to government estimates.

• 280,000. The number of jobs the American Petroleum Institute says could be created by offshore drilling in the Atlantic.

• 4.72 billion. The number of barrels of “technically recoverable oil” beneath federal waters from Florida to Maine, according to government estimates.

• $23.5 billion. The annual economic contribution that Atlantic oil drilling could bring to the U.S. economy, according to the oil industry.