N.Y.C. Admin. Code § 28-114.1.3: § 28-114.1.3 Personnel.

An approved agency shall employ experienced personnel qualified to conduct, supervise and evaluate the tests or inspections that it undertakes. Special inspections may be performed only by employees of such agency who are special inspectors qualified pursuant to department rules to perform or witness the particular test or inspection. The commissioner may require proof of the qualifications of employees.