The article reports the environmental accident caused by aerial pesticide spraying that reached the urban space of Lucas do Rio Verde-MT, in March 2006. It was characterized as a "major rural accident" of environmental and occupational aspects whose seriousness and extension crossed the agriculturally productive unit boundaries causing sanitary, social and environmental impact. This case study had as its objective the understanding of the social-technical scene of the accident and the monitoring process in health-environment in a research-action dynamic. The information was collected through interviews, documents and daily observation reports. It also referred to accidents, multidisciplinary and participatory analyses with the participation of local institutions of health, agriculture and environment, political and union leaderships, ranchers and farmers, the public prosecutor's office, journalists and the University. The study shows that the pesticide "use and abuse" monitoring actions have been extended to [a] "movement for the sustainable development of the region" supported by the participative monitoring and the fight for democracy and social justice in the search of a sustainable agriculture and/or environment.