Abstract: A minor amount of a radical trap, that is, an organic compound readily reacting with an organic radical, when combined with a polyolefin having a melt index of from about 0.2 to about 10, can be associated with 70 per cent tertiary butyl hydroperoxide (containing about 30 per cent water). In the event of accidental conflagration of the combination, the combustion continues at a moderate rate, thereby avoiding the propensity toward troublesomely rapid burning of unmodified aqueous 70 per cent TBHP. Container liners should have a polyolefin thickness of 0.7 to 7 mm, the polyolefin containing such radical trap in a concentration of from about 0.1 to about 5 per cent, generally 0.2 to 2 per cent. If particulate polyolefin is used, the radical trap concentration should be from about 10 to about 100,000 parts per million parts of aqueous TBHP. A concentration of polyolefin particles from about 0.6 per cent to about 6 per cent by weight of the TBHP is suitable.