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How to Dispose of Live Ammo Left by Police

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On Tuesday, Washington, DC, resident Ed Felten tweeted an image of a black bulb resembling a Christmas ornament, lying in a patch of spring grass. “Very relieved that the unexploded flash-bang grenade that my daughter found and innocently picked up this morning didn’t explode in her face,” Felten, former White House deputy chief technology officer, captioned the image. “Beyond angry that it was left on the streets of our capital city.”


Alongside the tweet were various reports of the previous night’s police assaults on civilians with stun (aka “flash-bang”) grenades, rubber bullets and chemical gas. Kicking off the evening, police memorably fired tear gas at peaceful protesters so that the president could take a photo holding a Bible upside-down outside St. John’s Episcopal Church.

A flash-bang grenade, detonated at short range, could most certainly cause serious harm: A ProPublica investigation has found that, in at least 50 cases, flash-bangs have burned, maimed, or killed Americans, including slicing off fingers and hands. “When these modified hand grenades explode on the human body, they can cause severe injury or death,” ProPublica wrote in 2015. “The flash powder burns hotter than lava.” In one 2014 case, a mother told the Atlanta Journal-Constitution that a flash-bang grenade police threw into her toddler’s crib “blew open his face and his chest.”


As militarized police and actual military forces meet protesters on streets across the nation, what should you do when you find leftover weapons of mass destruction and canisters of harmful chemical gas? Gizmodo asked experts for advice.

What happens if you pick up an undetonated flash-bang grenade?

William Atchison

Professor of Pharmacology and Toxicology at Michigan State University

Those [flash-bangs] are very dangerous, and if they explode (and the way they work is to explode), it would be far worse than holding on to a string of strong firecrackers when they detonate. Loss of fingers, perhaps a hand, and potentially blindness could ensue, so, by all means, do not touch anything like that.

What is your first step if you find a flash-bang, a tear gas grenade, or other munition?

Patrick Wilcken

Researcher, Arms Control, Security & Human Rights, Amnesty International

From our perspective, touching is definitely not advised, especially for all the different types of launched less-lethal grenades, whether they be flashbangs or CS gas [tear gas] or some combination. It’s hard to generalize, as there are many different designs, but if they are fired from a launcher they will contain propellants and other chemicals; if they are designed to emit sound or smoke, they will have small doses of explosive chemicals to detonate. They may also be very hot, having been fired at high velocity or recently detonated. There have also been cases of severe burns from handling canisters. Mace is likely to be less of a problem as it is normally a simple spray, though again, if there was mace residue, handling it could produce a skin or respiratory reaction.

We would always advise adults not to touch less lethal munitions, but if possible to document, by taking photos which have some indication of size and ideally including manufacturers’ markings (such as production codes). With this information, NGOs and other activists can pressure states and companies linked to human rights abuses though the manufacture or export of less lethal weapons. Children should stay well away.


Can you throw chemically contaminated riot control weapons in the municipal trash?

Marco Kaltofen

Founder of Boston Chemical Data Corp., a lab that investigates the transport and environmental fate of petroleum, chemical and radiological releases, and Associate Research Engineer at the Nuclear Science and Engineering Program, Department of Physics, at the Worcester Polytechnic Institute

Legally you need an ATF license to dispose or transfer an undetonated flash bang or CS device, and it must go to an ATF licensed entity. These can never go in the trash.

Stun grenades contain perchlorate, a significant water pollutant based on health effects in drinking water supplies. Use of flash grenades will affect nearby water supplies (just as municipal fireworks displays have damaged public water supplies).

This means that expended CS and stun grenades likely have residual material that is still dangerous to handlers. I’d rate these as in the same league as many household hazardous wastes (old fireworks, lead acid batteries, and other dangerous consumer goods). These would best be disposed of as industrial waste with a proper contractor.


What do chemicals, hurled into crowds, do to human health and the environment?

Hans Sanderson

Senior scientist and adviser for the National Environmental Research Institute of Denmark, Aarhus University, who has investigated the impacts of sea-dumped chemical weapons, among numerous other water contaminants

I would assume that the residue amounts released at use [by flash-bangs] will be quite low and not pose any significant acute risk to people or the environment. But again this can best be answered accurately on a case specific basis where the exact chemical constituents and amounts are known.

The effects of the intended smoke/gases (essentially chemical warfare agents) released such as teargas and other riot-controlling agents can be investigated further and could require some updating, Rothenberg et al (2016) found:

“Whereas tear gas deployment systems have rapidly improved—with aerial drone systems tested and requested by law enforcement—epidemiological and mechanistic research have lagged behind and have received little attention. Case studies and recent epidemiological studies revealed that tear gas agents can cause lung, cutaneous, and ocular injuries, with individuals affected by chronic morbidities at high risk for complications.”

Pepper spray is likewise potentially problematic but less researched than teargas (Gupta RC. Handbook of Toxicology of Chemical Warfare Agents. Academic Press; 2015).

Flashbang grenades I have no information about but would assume that the chemical exposures are far less than the other types above and thus from a chemical point of view a smaller problem—but again this can be investigated on a case-by-case basis and I don’t have that data at hand.

I would right now be most concerned about the use of teargas.

Who do you call to remove weapons left by law enforcement?

Vermont State Police

Speaking generally, any type of unexploded device, including a flash-bang grenade, is potentially dangerous if handled and should be avoided. People who encounter any device like this should stay away and call police or other first responders to safely remove the item.


Spokesperson, San Diego Police Department

If anyone comes across a ‘flashbang’ or any kind of device that looks like it is from the military or police, they should not touch it, back away and call 911.


Office of the Security Defense, Department of Defense

They should contact local law enforcement for tailored guidance.