Environmental Health Impact Assessment (EHIA) is the study of health-related illnesses and social conditions that may be linked to environmental exposures to toxic contaminants, and the health impacts of policies and other decisions that affect the environment. EHIA takes into consideration the complexity and interdependence of our relationship to the natural world. Sequoia's expertise in study design, survey development, fieldwork, sample collection, data analysis, and evaluation offer a unique opportunity for the protection and promotion of human health. Our community engagement and health education staff involve affected communities in the decision-making process that will affect their environment and/or health.  Their participation plays a significant role in guiding the decisions of state, federal, and local agencies in their communities.