Purpose: This Engineer Manual (EM) provides specific guidance, procedures, criteria, and tools for chemical implementation of the U. S. Army Corps of Engineers (USACE) HTRW Quality Assurance (QA) Program. Chemical QA is required to ensure analytical data generated for all projects meet the criteria prescribed by the technical project planning (TPP) team. This EM is intended for use by USACE personnel as a critical companion document to ER 1110-l-263.