D.C. Mun. Regs. tit. 20, r. 20-3250
No person or company shall conduct or offer to conduct radon screening, testing or mitigation in the District for a fee unless that person is currently certified as proficient by the American Association of Radon Scientists and Technologists, Inc. - National Radon Proficiency Program (AARST-NRPP) or the National Radon Safety Board (NRSB), or their successor organizations, or in the case of a company, employs at least one person who is certified by the AARTS-NRPP, NRSB, or their successor organizations.
No person or company shall use the name or title of "professional," "certified," or any other term that communicates a level of expertise in radon screening, testing or remediation, unless that person is certified as proficient under § 3250.1, or in the case of a company, employs at least one person who is certified as proficient under § 3250.1.
All persons using such names or titles as referenced in § 3250.2 or conducting such activities as listed in § 3350.1 shall provide to the Department their name and AARST-NRPP or NRSB issued certification or identification number upon request.
All companies using such names or titles as referenced in § 3250.2 or conducting such activities as listed in § 3250.1 shall provide to the Department the name and AARST-NRPP or NRSB issued certification or identification number of each of its employees that perform the activities listed under § 3250.2 upon request.
D.C. Mun. Regs. tit. 20, r. 20-3250