We classify incidents according to their severity: $ a major environmental incident is associated with widespread, long-term, irreversible (within five years) negative ecological impacts with a high risk of legal liability; $ a moderate incident is associated with a widespread or localised, medium-term, reversible (within five years) significant ecological impact and/or has a risk of legal liability; and $ a minor incident is limited to the immediate area of occurrence associated with a short-term ecological disturbance, environmental nuisance or a transgression of an internal standard (including complaints from interested and affected parties) that does not result in any environmental impact after a once-off internal intervention.