The paper describes a few aspects of the vessels' safety in a sea port, taking into consideration the effect of location of cargo-handling and berthing quays for vessels with dangerous cargo. The concept of "danger zone" in the port has been defined, based on the possibility of either force-majored or intentional threats of collisions with other vessels, and threats created by neighbouring cargo-handling stations. Protective measures have been suggested in compliance with the ISPS convention and EU require-ments.