A Blast Ball (also known as a "Tear Ball" or "Rubber Ball Grenade") is a ball-shaped, rubber coated, less-lethal hand grenade designed for police and corrections applications. A Blast Ball is similar to a traditional "flash-bang" grenade in that, when detonated, it generates a loud noise and bright light. In addition, however, a Blast Ball will also release a chemical irritant, either OC gas or CS gas.
Blast ball Wikipedia
Blast Balls can be used against aggressive crowds during situations in which rioters significantly outnumber police or prison guards. In this application scenario, they are intended to frighten away and disperse "casual" rioters, or those who have been "sucked into" the contagion of the crowd, allowing police or prison guards to close with, and engage, the remaining "hard core" element.
One typical deployment of Blast Balls occurred during the 2011 Vancouver Stanley Cup riot and was described by a Vancouver Police Department officer:
Blast balls can also be used to create "negative stimulus" by detonating in areas toward which police do not want the crowd to move, allowing a "herding" effect.
Blast Balls are marketed by AMTEC Less-Lethal Systems and by Combined Tactical Systems.
A 2015 lawsuit by a woman in Seattle, Washington alleges shrapnel from a Blast Ball penetrated her leg. Seattle Police Department has said tests show that a Blast Ball detonated at contact range against ballistic gel fails to produce trauma or tearing.
Blast Balls manufactured by AMTEC Less-Lethal Systems weigh 212 grams and contain either 14 grams of OC gas or 12 grams of CS gas.