Special Feature

Sonic Device for Crowd Control: Too much for human ear

03 Feb,2018

BdChronicle Special Feature:

The controversial sonic device procured recently by the police to disperse protesters has the potential to damage nerve system of ears for good, according to doctors and records.     

When equipped with HS-16 Acoustic Hailing Device (AHD), the device in question, a trigger-happy cop also runs the risk of causing serious nerve injury to many, mostly innocents, if it is used at the maximum volume on a crowded street.       

Police, who added 12 AHDs to their crowd-control armoury last year at a cost of Tk 50 lakh each, are happy with the results as the piercing sound can drive protesters at least one kilometre away from the device mounted on a vehicle.    

Presently, police use batons, water cannons, teargas shells, rubber bullets, shotguns and sound grenades for crowd control.

“We bought the device for effective crowd control to avoid any unexpected incidents,” Tanvir Momtaz, assistant inspector general (equipment) of the Police Headquarters, told The media recently.

Asked about the justification for buying these device, police officials said AHDs are an effective tool to control crowd without needing to go anywhere near the targeted gathering. When used, there will   be no chance of violence because the demonstrators will not be able to engage in clashes with the law enforcers. 

It may be effective, but health experts warn it could damage nerve system of ears of people within a kilometre range, and the available treatment is of little help. 

Manufactured by an American company, HyperSpike Technology, the device looks like a heavy-duty speaker (weighing over 16kg) and discharges up to a deafening 148-decibel sonic beams.

Mohammad Abdullah, a professor of Ear, Nose and Throat at Dhaka Medical College Hospital, said this could cause immediate damage to the nerve of ears.

“Repeated exposure to such a high level of sound may also permanently damage the ear nerves, leaving a victim hearing impaired,” said Abdullah, adding, “Treatment cannot usually fix the damage.”

A normal conversation is usually 60 decibels, a lawn mower could emit up to 90 decibels, and the pain threshold for most humans is 130 decibels, according to international media reports.

Exposure to sound levels over 85 decibels can cause hearing loss, according to US's National Institute for Occupational Safety and Health.

On November 30 last year, police used one of the AHDs at Shahbagh for the first time during a half-day hartal by left parties.

A number of demonstrators, hawkers and passers-by complained of dizziness for hours even though they fled instantly, covering their ears with their palms.

They also said they puked within an hour of being exposed and had splitting headaches.

“I had the discomfort till I fell asleep. I only felt better after I woke up the next morning,” Jamal, a 15-year-old betel leaf vendor, told The media a week after the incident.

But officials at the Police Headquarters played down the concerns, insisting that there was no chance of people being harmed as only trained commanders are authorised to use it.

The commanders use AHDs at least 20 metres away from the crowd and the device only allows five-second bursts at 148 decibels. If the device is used for more than five seconds,          the decibel level drops to 74, officials said.  

The commanders have also been trained to keep the volume between 50 to 65 decibels if the device is used for more than one minute, they  added.

But rights activists say police seldom follow rules while using even the conventional crowd-control weapons.

On July 20 last year, Titumir College student Siddiqur Rahman became blind after a teargas canister fired by a constable hit him in the eye. 
Under the rules, tear shells should be fired upwards, at a 45-degree angle.

Rights activists also pointed out the safety concerns in a densely populated city like Dhaka.

“I don't think Dhaka is a place where such a sonic weapon can be used,” Nur Khan Liton, a noted human rights activist, told The media.

“No matter how firm the police are in their claim that the commanders are trained and they would work within the law, our past experience is that they do many things going beyond the law,” he said. 

Initially designed for military use, the sound weapons were used in war zones in Iraq and Afghanistan to get people out of buildings into the range of snipers.

Police in many countries, including the US, Canada, Australia and India, now have LRADs, a type of AHD. The use of the device sparked uproar in almost all countries, and in some cases courts had to weigh in.

The most-publicised victim of the device was Karen Piper, a professor at University of Missouri, who was blasted with the device by Pittsburgh police while taking footage of protestors at the G-20 summit in 2009.

Prof Piper said she had bad ringing in her ears for a year that drove her crazy but more seriously, she discovered she also had permanent hearing loss.

“It's actually nerve damage ... and those nerves will never recover,” she told ABC in 2016.

The English professor was the first person to sue authorities over the use of such device and eventually reached a settlement with the City of Pittsburgh for $72,000.

Meanwhile, political activists questioned the police procurement of such a crowd-control weapon that generated so much criticism  globally.

“The government should be more careful about purchasing any device for police that goes against public interest,” Baki Billah, an activist and former president of Bangladesh Student Union, told The media.

No one in the Police Headquarters was willing to talk about the process of buying these devices.

On condition of anonymity, one official said, “Approval from a technical evaluation committee was taken before the purchase, as required by government rules.”

But he could not tell if the committee had a medical expert on it. 

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