A supplier must generate three Performance InCheck Reports within the specified time limit before advancing to a Verified InCheck - Level 1. The supplier can engage with any of the ZDHC Approved  Verified InCheck Providers listed on the ZHDC Find Your Expert website. For the on-site due diligence, the suppliers should do the following:

1. Mutually agree on the date of visitation with the confirmed reviewer
2. Download the PDFs and Excel documents of the chemical inventory in each of the past three reports from their Gateway account and mail this to the reviewer prior to the visit.
3. Share the site map (preferably with the chemical stores marked on the map) with the reviewer prior to the visit.
4. Keep chemicals-related documents ready for due diligence. These are SDS, purchase orders, contracts with chemical vendors, CIL records, production recipe sheets, etc.
5. During the site visit, allow the reviewer access to all chemical main and sub-stores, and production areas.