The effects of storage conditions on some fungicide pesticides, metalaxyl modified by mancozeb represented in acimaxyl 72% WP, and copper modified by mancozeb represented in triomax 66% WP were investigated. The results revealed that the degradation rates for acimaxyl 72%WP and triomax 66% WP differed during storage, with the calculated half-life values for acimaxyl being (149.48 days for mancozeb and 43.33 days for metalaxyl) and (113.64 days for mancozeb and 104.24 days for copper) in triomax. After 14 days at 54 ⁰C, the effect of thermal storage on the synthesis of ethylene thiourea (ETU) in mancozeb was raised to 0.222% for acimaxyl and 0.160 % for triomax. Furthermore, the influence of oven temperature on storage 2,6 dimethyl aniline impurity in acimaxyl (mancozeb 64% and metalaxyl 8% ) was 0.020% before storage and 0.040% at the end of the experiment storage time. Before and after storage at 54 ⁰C, the levels of lead, cadmium, and arsenic (mg/kg) as well as metallic copper were measured in triomax 66% (mancozeb 12%, and copper 29%). The levels of cadmium and arsenic were fewer than FAO limits, whereas lead was more than FAO limits. The data showed that metallic copper in triomax formulation remained generally consistent over time.