What are the conditions that classify a discharge as 'harmful'?

A discharge is classified as 'harmful' when it causes visual evidence of pollution, such as foam, sheen, or discoloration in the water. This is critical because these signs indicate that the discharge may have negative effects on aquatic life, water quality, and the ecosystem as a whole.

Visual indicators like foam or sheen often suggest the presence of oil or other hazardous substances, which can be detrimental not only to marine organisms but also to human health and local economies that depend on clean water. Identifying these visible changes is essential in assessing the potential impact of the discharge and in mobilizing the appropriate response measures.

The other conditions listed do not adequately define what makes a discharge harmful. The absence of visible changes does not imply that a discharge is not harmful, nor is merely reporting to authorities a criterion for harm. Observations during recreational activities alone do not address the environmental impact of discharges without visible signs of pollution.