The purpose of this book is based on the principles of precaution and solidarity. Its main objective is to contribute to the activities of prevention, preparedness and response to environmental accidents in port areas, from the ecosystem point of view. Studies on risk perception surveys, on causes and consequences of accidents, and about people´s behavior during these accidents, are useful to enrich risk management programs, and emergency plans. This content was elaborated based on the postgraduate studies in Environmental Sciences at USP/SP, and the post-doctorate in Psychology at PUC/SP. All of them involved analysis of environmental accidents in port areas of São Sebastião and Santos (SP), and risk perception surveys. Adds to this the author's 30-year experience at the environmental agency of São Paulo state (1988/2018). This book comments on 60 accidents, technological and/or influenced by natural phenomena, in the Brazilian ports and abroad, from 1900/2019. There were highlighted topics such as: people´s reactions in dangerous situations, social and environmental consequences, risk perception of effects on human health, and oily fauna, among others. The work concludes that people which are very curious, opportunistic and reckless can amplify the consequences of these episodes. It highlights that cautious, supportive and altruistic people help to minimize them, when they act with knowledge, discernment and goodwill. The investments in prevention and preparedness have helped to reduce the number of accidents and it´s severity, so they should have continuity, in an effort that catastrophic situations do not repeat.