Before they unleashed bursts of ear-splitting sound to scatter rowdy protesters, city SWAT officers tested the Long Range Acoustic Device on themselves to see if it was safe.
No one went deaf.
Pittsburgh police said the first use of the LRAD to disperse protesters in the United States last week was a success, but demonstrators complained the loud, shrill noises the device emitted worsened a tense situation and raised the likelihood of violence.
"A large contingent of the SWAT officers got exposed to the sound (during tests). It went well," said Ray DeMichiei, the city's deputy director of Emergency Management.
No long-term studies have been done of the device's effects. However, the damage that loud sounds can cause is well studied, said Dr. Doug Chen, director of the division of neurotology at Allegheny General Hospital.
"It appears that this device can damage hearing, but in terms of the alternatives, it's probably safer than a Taser or a billy club," he said.
DeMichiei's department prepared a report before the Group of 20 summit on nonlethal technologies that would be useful in controlling huge crowds of protesters that, ultimately, didn't materialize. Officials estimated 5,000 protesters took to the streets during a peaceful Friday afternoon march.
At a cost of $200,000, city and county SWAT teams used federal Homeland Security money to buy four of the devices. DeMichiei said the technology is novel, but not dangerous.
"Any of the effects are transient," he said. "The only long-lasting effects are if you are exposed to the maximum and you're exposed to it for a long time."
City police Officer Steve Mescan, a SWAT team member, said he experienced the sound during a test, but declined to discuss it without approval from superiors.
The LRAD, manufactured by San Diego-based American Technology Corp., has a maximum "burst" volume of about 150 decibels, a level roughly equivalent to artillery fired at close range.
Occupational Health and Safety Administration guidelines state that a worker can suffer hearing loss if exposed to 120 decibels — a loud rock concert — for more than seven minutes at a time over a long term.
"At 130 decibels, that is considered acoustic trauma versus just noise. Acoustic trauma can produce permanent hearing loss even with brief exposure," Chen said.
During the protests, police broadcast prerecorded verbal warnings and played a high-pitched oscillating tone akin to a car alarm to disperse protesters who either fled or covered their ears.
Similar to a spotlight, the LRAD usually is mounted to a swivel on a vehicle. The operator can target the sound through a scope.
The device sends out a "cone of sound" 30 degrees wide for a distance of about 1,000 feet, or three to four city blocks. Ambient noise from the device can be heard two miles away.
Heidi Boghosian, executive director of the National Lawyers Guild, stood next to the device on Penn Avenue when police broke up an unauthorized march Sept. 24 from Arsenal Park in Lawrenceville to Downtown.
"I didn't feel any pain, but it was very irritating," said Boghosian, whose organization coordinated dozens of legal observers to watch for civil rights violations. "The effect was kind of like being in a war zone."
Robert Putnam, a spokesman for American Technology Corp., said he has been exposed to the LRAD hundreds of times.
"My hearing is fine. You're talking to me in a normal voice and I'm hearing every word you're saying," Putnam said.
Putnam could not provide the number of units in use. Cruise vessels off the coast of Africa have used the LRAD to ward off Somali pirate ships; Boston police used it to direct crowds after the Red Sox's World Series victory in 2004.
"It has a volume control on it rather than tear gas or rubber bullets, which, once they're gone, they're gone," Putnam said.
American Technology Corp. isn't the only manufacturer of acoustic hailing devices.
Indiana-based Wattre Corp. produces the "Hyperspike," which can be used for border patrol, mass notification and search and rescue, according to the company's Web site. Power Sonix, Inc., of Martinsburg, W.Va., also makes hailing devices that can be mounted to helicopters or carried by infantrymen.