Ecotoxicological and occupational health hazards triggered by pesticide usage are strictly linked to the technical wear of application equipment. This study applies the industrial FMECA (Failure Mode, Effects, and Criticality Analysis) methodology to a pool of 294 knapsack sprayers operated in vegetable farming across three key zones of Côte d'Ivoire (Abidjan, Bouaké, Korhogo), alongside an assessment of growers' cognitive risk boundaries. Technical audits expose that 85% of sprayers are defective, reaching 88% in Abidjan. Pumping lever jams (211 cases), cracked tanks (105 cases), and unsealable caps (111 cases) emerge as primary structural anomalies. The FMECA approach ranks unnoticeable nozzle orifice expansion (Criticality = 40) and leaking tank caps (Very High Criticality = 48) as priority operational hazards inducing involuntary overdosing and direct dermal operator exposure. Simultaneously, a deep cognitive dissonance was documented: 96% of Abidjan market gardeners implement no water resource protection measures, undermining chemical toxicity for short-term financial trade-offs. Urgent equipment calibration and participatory safety protocols are highly critical.