A dye pack is a radio-controlled incendiary device used by banks to foil a bank robbery by causing stolen cash to be permanently marked with dye shortly after a robbery. They were invented in Georgia in 1965. In most cases, a dye pack is placed in a hollowed-out space within a stack of banknotes, usually $10 or $20 bills. This stack of bills looks and feels similar to a real one, with technology allowing for the manufacturing of flexible dye packs which are difficult to detect by handling the stack.
When the marked stack of bills is not used, it is stored next to a magnetic plate near a bank cashier, in standby or safe mode, ready to be handed over to a bank robber by a bank employee. When it is removed from the magnetic plate, the pack is armed, and once it leaves the building and passes through the door frame, a radio transmitter located at the door triggers a timer (typically at least 10 seconds), after which the dye pack explosively releases an aerosol (usually of Disperse Red 9) and sometimes tear gas, intended to destroy the stolen money and mark the robber's body with a bright stain. The chemical reaction causing the explosion of the pack and the release of the dye creates high temperatures of about 200 °C (392 °F) which further discourages a criminal from touching the pack or removing it from the bag or getaway vehicle. Dye packs are used to foil robberies in over 75% of banks in the U.S.
In England, a robber who fled a bank in Regent Street laughing "Haha, I've got all the money", was enveloped in "a red cloud" of dye as he ran away down Shaftesbury Avenue. He was later caught and jailed.
- Di Paola, Jim (19 November 1989). "DYE PACKS FOIL BANK ROBBERS' CLEAN GETAWAYS". Sun-Sentinel.com. Retrieved 17 July 2019.
- "I've heard of bank robbers being foiled by a 'dye pack' put in their money stash. What is a 'dye pack'?". How Stuff Works. Retrieved May 21, 2012.
- US5485143A, Keniston, "Security dye pack having flexible heat-resistant chemical pouch", published 1993
- "Thieves caught after dye pack explodes in bank heist". New York Post. Retrieved October 23, 2016.
- "Jailed, laughing robber who was covered with security dye". London Evening Standard. 14 July 2014. p. 5.