Why are sample numbers missing from the groundwater samples collected between May and November of 2021?

EPA reviewed Navy analytical data for sample IDs that were skipped by comparing results from lab reports to samples listed on Chain of Custody forms (CoCs). We did not find sample IDs listed on the CoCs missing from the laboratory results. Sample numbering isn’t always sequential because sample IDs may be preassigned, cancelled, or reserved for quality control needs. Although this can look like “gaps,” our review did not find any deviation from the required sampling frequency that would indicate samples were missing.