Abstract: A low viscosity liquid pyrophoric composition, which provides good safety der ordinary handling conditions but ignites rapidly when disseminated into the atmosphere, consists essentially of about from 50% to 85% by weight of a homogeneous solution of polyisobutylene in triethylaluminum and about from 15 to 50% of a saturated aliphatic hydrocarbon of 5 to 12 carbon atoms, said composition having a viscosity ranging about from 30 to 150 centistokes at 40.degree. C. When explosively disseminated into the atmosphere, the composition generates a fireball having a controlled ignition delay, which permits essentially complete vaporization of the hydrocarbon prior to ignition of the TEA, thereby producing rapid pulses of intense thermal radiation having a temperature as high as 1200.degree. C. (2192.degree. F.) and higher.