Three tons of ammonium nitrate, the chemical compound commonly used in bomb making, was seized in Ontario, Canada in early June. Seventeen Canadian citizens arrested for "terrorism related offenses" reportedly had amassed enough explosives to blow up multiple targets around southern Ontario, Canadian police said. To put the quantity of ammonium nitrate seized into perspective, one ton was used in the bombing of the Murrah federal building in Oklahoma City in 1995, which killed 168 people. Those arrested were all citizens, and of a variety of backgrounds, according to Luc Portelance, Assistant Director of Operations for Canadian Security Intelligence Service. They reportedly believed in the ideology inspired by al Quaeda, although there was no immediate evidence that they were sponsored by the terror organization.

Over 400 Canadian police, border and intelligence agents and security forces were involved in the operation.

Ammonium nitrate is a strong oxidizer which is used widely in agriculture and industry and also is used as an ingredient in improvised explosive devices. When oxidizers are heated, these highly reactive products decompose and give off oxidizing gases which accelerate the burning of combustible material. They may react violently or explode when they are mixed with ordinary combustibles. Closed containers may rupture violently when heated. For more information about ammonium nitrate, including the safe response to incidents involving ammonium nitrate and other oxidizers, see Emergency Film Group’s training program “Inorganic Oxidizers.”