Why is there any doubt about where blame lies for the Grenfell Tower fire?

Until retirement, I was an offshore design engineer designing mechanical systems for oil/gas rigs and wind farm converter platforms all over the world.

There was not one component that was not individually fire-tested, certified and, if part of a composite structure, tested along with the intended components to be part of the composite.

OTHER NEWS:

This was rigorously applied to cladding composites both internal and external.
No offshore structure can be tolerated that does not have a registered certification dossier proving compliance with the many standards applicable – particularly those elements.

Such dossiers would have to be approved by Certification Bodies such as Lloyds, DnV etc. Without this, an offshore structure cannot be insured.

What compliance checks did the insurers of Grenfell Tower make?

You surely cannot blame suppliers for poor materials as they would/could only provide what was specified.

I have to add that in 40 years of practice I did work on one or two land-based jobs (when offshore work became scarce) and I was surprised at the stark difference in safety standards.
Peter Williams
Caersws