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Credentials and classifications

The credentials behind every engagement.

Two credentials, one for each half of the obligation. ADA Coordinator Certification governs the program: designation, self-evaluation, transition planning and grievance process. The Department of Homeland Security Trusted Tester process governs the technical standard. One firm delivers both, so a public entity does not run two procurements to meet one obligation.

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How to confirm each one

Two of these can be checked directly: the NYC certification in the City's public directory, and the federal identifier on SAM.gov with a free account. City procurement staff can confirm the PASSPort record. For the two certifications, a copy of each certificate comes with any written inquiry, and each row below names the issuer.

  • ADA Coordinator Cert. (ADACC)55147918-4622
  • Department of Homeland Security Trusted TesterTT-2604-08987
  • NYC Minority Business EnterpriseMWCERT2025-1083
  • Federal UEI, SAM.govE2Q7D9LYPM54
  • NYC Vendor, PASSPortVS00099772
  • NAICS541611 · 541519

Certifications and registrations

  • ADA Coordinator Certification (ADACC)The program credential. Issued by the University of Missouri, College of Arts and Sciences, Department of Architectural Studies, through the ADA Coordinator Training Certification Program (ACTCP). Approved designation ADAC. Current through May 2027 and renewed each year. The program doesn't publish a lookup, so the certificate comes with any written inquiry55147918-4622
  • Department of Homeland Security Trusted TesterThe technical credential. Issued April 22, 2026 by the U.S. Department of Homeland Security, Customer Experience Directorate. The federal manual testing process for Section 508 conformance. DHS doesn't publish a registry of certified testers, so the certificate comes with any written inquiry; DHS takes questions about the program at accessibility@hq.dhs.govTT-2604-08987
  • NYC Minority Business EnterpriseNYC Department of Small Business Services. Search the NYC Online Directory of Certified BusinessesMWCERT2025-1083
  • Federal entity registrationSAM.gov Unique Entity Identifier. Searchable on SAM.gov with a free accountE2Q7D9LYPM54
  • New York City vendorNYC PASSPort. City procurement staff can confirm it in PASSPortVS00099772
  • Legal entityGuillaume & Co. LLC, New York domestic LLCDOS ID 7265133
  • Industry classificationNAICS codes carried on the federal registration, listed in order of fit to the work performed541611 · 541519 · 541511 · 541512 · 541990
  • Federal size statusSmall business under the SBA size standard for NAICS 541611Small business

Trusted Tester is the manual testing process federal agencies use to validate Section 508 conformance. Certifications are held by the practitioner and are not an endorsement of this firm by the University of Missouri, the Great Plains ADA Center, or any federal agency.

Who signs the work

Accessibility certifications are held by people, not by companies. Work is performed and signed by certified personnel of the practice, and testing is never subcontracted to a scanning vendor.

Marc Guillaume

Principal

Department of Homeland Security Trusted Tester, certificate TT-2604-08987. ADA Coordinator Certification, ADACC 55147918-4622. Certificates come with any written inquiry.

Before founding the firm, the principal worked for the New York City Department of Education as a Disability Service Facilitator, surveyed more than 500 of the City's school buildings for accessibility, and presented at the Beyond Access Forum in 2022.

References and work samples available on request under appropriate confidentiality terms.

What this means for buyers

The classifications below affect how your procurement office can contract with the practice.

City contract eligibility

Eligible for New York City contract set-asides and bid preferences as a certified Minority Business Enterprise.

NYC SBS certified

Listed in the public directory

Listed in the NYC Online Directory of Certified Businesses, so a procurement officer can confirm status independently.

Independently verifiable

Prime contractor participation goals

Engagement supports a prime contractor's M/WBE participation goals on City contracts.

Subcontract ready

Federal identifier

Unique Entity Identifier E2Q7D9LYPM54, assigned in SAM.gov, for federal contracts and federally funded subawards.

SAM.gov UEI

Put these credentials to work

Whether you are a procurement officer vetting a vendor or an organization that needs a credentialed audit, a short call clarifies fit and scope.

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