Abstract Rapeseed containing up to 1 ppm malathion and ≤ 10% moisture was stored for up to 32 weeks at 10, 20 and 30°C to determine the time required to reach residue levels of 0.1 ppm. Malathion levels < 0.1 ppm were found only in seed at 20°C, 7.7% moisture content by 32 weeks and at 30°C, 7.1% moisture content by 16 weeks. The malathion degradation rates were related to calculated safe storage times to determine acceptable storage conditions. An improved analytical method of malathion extraction from rapeseed was developed. Manipulation of temperature ≤ 60°C for short periods was ineffective in lowering malathion residues to 0.1 ppm.