<p>At-sea containment and recovery is the controlled encounter and collection of oil from the water’s surface. Equipment is used to corral and concentrate the spilled oil (using floating barriers or booms) on the sea surface into a suitable surface thickness, allowing for mechanical removal. This document explains how effective containment and recovery can reduce the impact to on-water sensitivities such as seabirds, fish and mammals; reduce the impact on shoreline sensitivities by removing floating oil at sea; reduce the complexity and duration of a shoreline response, and reduce the volume of waste generated by a response. The document explores the reasons why at-sea containment and recovery sometimes fails, and the circumstances under which it can and cannot be considered.</p>