Imagine if your home was periodically and without warning inundated by a piercing wail so obtrusive that it disoriented and nearly blinded you. A sound so painful and terrifying that it sent you running willy-nilly off a cliff or the roof of a building.

According to the Natural Resources Defense Council (NRDC), this is a rough analogy for what’s happening to some of the ocean’s marine mammals.

On Nov. 21, the NRDC released a report stating that marine mammals like dolphins and whales that rely on sound for mating, finding food and avoiding predators are being threatened by increasing levels of ocean noise generated by military sonar, shipping and oil and gas exploration.

Based on necropsies performed on beached whales suspected of being exposed to US Navy sonar, the report details bleeding around the brain and ears, and lesions in the animals’ livers and kidneys. Researchers believe the mammals are suffering from what scuba divers call “the bends,” decompression sickness cause by surfacing too quickly or staying too deep too long. The leading theory posits that the Navy’s mid- and low-frequency sonar tests are panicking the mammals into unnatural behavior.

Last month the NRDC sued the Navy to curb its use of mid-frequency sonar. The environmental group wants to limit the Navy’s use of the submarine-detecting technology to wartime, and force them to obtain a permit for its sonar exercises.

In response, the Navy is taking initial steps towards limiting its sonar use. Citing a need for consistent anti-submarine warfare training opportunities, the Navy is working to establish a 500-square-mile training range, 50 miles off the coast of North Carolina. The site, dubbed the Undersea Warfare Training Range, will be host to up to 48 mid-frequency active sonar exercises per year, plus 113 exercises using other, somewhat less intense acoustic sources.

Noise pollution in the world’s oceans is an issue that’s been rapidly gaining attention, and in the last five years, the Navy has been under increased criticism.

After international scientific organizations issued reports supporting a link between active sonar and whale deaths, the European Parliament voted 441 to 15 to urge member nations to cut back on active sonar use in European waters, and to create a multinational task force to develop agreements regarding sonar and other intense ocean noise.

Last April, Rep. Sam Farr joined Sen. Barbara Boxer and other Democratic lawmakers in asking the Office of Ocean Affairs and the Department of State to reconsider a new US policy that bans any efforts to limit the global use of sonar through international negotiations—despite the fact that evidence of marine mammal harm has become more conclusive.

“Scientific investigations, including some by our own military, have linked the use of active sonar with mass mortalities of whales and other marine mammals,” Farr says. “I think it’s clear that we must find a better balance between the military’s need to use sonar and the need to protect marine life.”

Yet even more concerning than mid-frequency testing is Low Frequency Active Sonar (LFAS) testing, which has been proven to also affect humans, particularly scuba divers. Surveillance Towed Sensor System Low Frequency Active Sonar (SURTASS LFAS) is also used by the military to detect submarines. While the sonar system is “low frequency,” it is also extremely loud. At maximum output, the system can generate sound up to 230 decibels, which is 10,000 times louder than a 747 taking off. Underwater, these sounds travel tremendous distances.

The first unannounced experiments with LFAS, held north of the Farallones Islands, were called “The Magellan Tests” because they were sounds heard around the world.

In a 1996 study, a 32-year-old Navy diver suffered dizziness, inability to concentrate and other symptoms after 12 minutes in water with 160-decibel sound. Though he received immediate medical attention, he relapsed after an hour and again the next day. A year later, he suffered a seizure and was treated with anti-depression and anti-seizure drugs.

It’s an unpleasant and life-altering experience to which Carmel Valley resident Jay Murray says he can attest.

On Aug. 25, 1994, Murray was scuba diving off Point Lobos with two buddies. As he began his descent, Murray experienced an unusual, pulsing low frequency sound, which disconcerted him enough to ascend.

“I surfaced immediately to see if there were any vessels in the area that could have been producing it, but there was nothing in sight,” Murray says. “At that moment I thought, since the Cold War was over, the only organization that would do something like this would be the United States Navy.”

The next day Murray returned and recorded the sound, a one-second pulse that occurred variably between three to 10 seconds, with an underwater video camera. According to Murray, he took the tape directly to the Naval Postgraduate School.

“Within 48 hours of me delivering the tape, CNN, NBC and ABC News had picked up the story and it was running across the United States,” Murray says.

Although officials at NPS deemed Murray’s recordings inconclusive, Murray believes the low frequency sound he heard was the Magellan Tests. According to a 1999 CNN report, other Monterey Bay divers also reported “deep, heartbeat-like thumping” at times from July through November. Over the next 10 months, Murray says he experienced the strange low frequency pulses 20 times while diving.

“It produced a definite negative reaction,” he says. “It destroyed sleep patterns and I experienced classic depression. In the middle of the night, I found myself with tears running down my face thinking about all the marine life out there.”

Murray says his depression eventually “morphed into continual anger.” Convinced that the Navy’s tests were both negligent and potentially life-threatening, Murray has been waging a one-man war against the Navy’s use of LFAS.

Shortly after his experience at Point Lobos, Murray blasted his recording of the underwater pulses through a 15-inch subwoofer powered by a 100-watt amp outside a 1995 Coastal Commission meeting in Carmel.

“That got their attention, but didn’t really accomplish much. I’ve been somewhat extreme around here at times,” Murray admits. “But there’s no one else to do it.”

After spending roughly $25,000 on hydrophones, digital audio tape recorders, a laptop computer, speakers and a housing for an underwater camera and microphone, Murray began capturing the sound off the coast of Monterey. He analyzed the sounds and says he gave the data to the NRDC.

“I provided the Senior Attorney Joel Reynolds copies of my printouts and he took them to Washington and threatened the Navy with a lawsuit unless they conducted an environmental impact report on the low frequency active sonar system,” Murray says.

Ultimately, Murray’s data was instrumental in NRDC’s successful efforts to force the Department of the Navy Chief of Naval Operation Overseas to publish their “Environmental Impact Statement and Environmental Impact Statement for Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) Sonar” in 2001.

Yet despite the fact that SURTASS LFA’s detrimental effect on marine mammals is well documented, the Navy continues to conduct LFAS tests.

Additionally, the Navy is preparing to deploy four new SWATH (Small Water Area Twin Hull) vessels equipped with the undersea surveillance technology.

Beginning Dec. 1, hearings will be conducted in Washington DC, San Diego and Honolulu to give the public an opportunity to comment on the Navy’s proposed action to employ these four SURTASS LFA sonar systems in the oceanic areas of the Pacific, Atlantic, and Indian oceans, and the Mediterranean Sea.

FOR MORE INFORMATION, VISIT WWW.NRDC.ORG.