4. Where venting is allowed pursuant to paragraphs 2 and 3, operators shall vent only where flaring is not technically feasible due to lack of flammability or inability to sustain a flame, risks endangering safety of operations or personnel or where it would have a worse environmental impact in terms of emissions. In such a situation, as part of the reporting obligations set out in Article 16, operators shall notify and provide evidence to the competent authorities of the necessity to use venting instead of flaring.