how do I answer the question whether we use hazardous substances in our production process

Hazardous substances is broader than the hazard list alone

The answer depends on how you read "hazardous substances", and that is precisely where this question goes wrong in practice. VSME does not ask this as a standalone question but as part of the environmental module: is it about substances with a hazard classification according to the CLP Regulation (flammable, corrosive, toxic, environmentally hazardous), or about everything that comes with a safety data sheet? Most customer portals mean the first: substances that have a CLP hazard pictogram somewhere in the process, regardless of the quantity. Cleaning agents, solvents, paint, coolant and batteries often count, even if the main activity has nothing to do with them.

The evidence is usually not a single document but a sum: the list of safety data sheets (SDS) you have from suppliers, linked to an overview of which of those have a hazard classification. If you don't have that link readily available, then "no, as far as known" with an explanation is more honest than an unfounded "no". A separate inventory of hazardous substances — as some environmental permits already require — is the strongest evidence, but not every business has that separately. That overlaps with the question of whether you have the required environmental permits in order: that permit often already states which substances are permitted and in what quantity.

Where this comes from: VSME environmental module

This question appears in the basic module of EFRAG VSME, in the section on pollution and hazardous substances, and aligns with the CLP hazard classification used there as a reference. It is separate from the scope 1, 2 and 3 classification of the GHG Protocol, which concerns greenhouse gas emissions and not substance hazard — a distinction that is useful if your customer combines both questions in the same list, as happens with the scope 1, 2 and 3 question that is often asked together. If in doubt, check whether your customer explicitly refers to CLP classification or uses a broader, own definition.