§ 120. Custody and supervision of persons in correctional facilities. 1. Except as provided in subdivisions two, three and four of this section, the duty of maintaining the custody and supervision of persons detained or confined in a correctional facility as defined in subdivision four of section two of this chapter, including a drug treatment campus as defined in subdivision twenty of section two of this chapter, or a local correctional facility as defined in subdivision sixteen of section two of this chapter shall be performed solely by police officers designated in paragraph (a), (b), (c), (d), (e), (g), (j) or (m) of subdivision thirty-four of section 1.20 of the criminal procedure law or peace officers designated in subdivision twenty-five of section 2.10 of the criminal procedure law, which persons, whether employed full-time or part-time, shall be in the competitive, non-competitive or exempt class of the civil service of New York state as determined by state law or by the state or applicable local civil service commission.

2. Nothing in this section shall limit in any way the authority of the commissioner, or any county or the city of New York, to enter into any contract authorized by subdivision eighteen of section two, section seventy-two-a, section seventy-three, section ninety-five, article five-A or article twenty-six of this chapter, or to limit the responsibility of the department of corrections and community supervision to supervise inmates or persons released to community supervision while away from an institution pursuant to section seventy-two-a, section seventy-three or article twenty-six of this chapter or while confined at a drug treatment campus as defined in subdivision twenty of section two of this chapter.

3. Subdivision one of this section shall be inapplicable to any person who is or may be employed in a correctional facility as defined in subdivision four of section two of this chapter or a local correctional facility as defined in subdivision sixteen of section two of this chapter or who contracts or may contract to provide services at such a correctional facility, who, in either case, is (a) not a correction officer or deputy sheriff, and (b) does not have, as their primary job responsibility, the duty of maintaining the supervision of persons detained or confined in a correctional facility but who provides such supervision as a secondary, ancillary or incidental part of their primary employment responsibilities. An employee who meets the criteria provided by paragraphs (a) and (b) of this subdivision may include, but not be limited to, food service, janitorial or maintenance staff of such a correctional facility or persons who provide health care, substance abuse treatment, counseling, religious, educational or vocational services at such a correctional facility.

4. Nothing in this section shall preclude an elected or appointed sheriff, the commissioner of correction of the city of New York, the commissioner of the Westchester county department of correction, or any other municipal official in the unclassified service, as determined by state law or by the state or applicable local civil service commission, from maintaining the custody and supervision of persons detained or confined in a local correctional facility as defined in subdivision sixteen of section two of this chapter. Provided further that nothing in this section shall be construed to limit or affect the existing authority of the mayor of the city of New York and the commissioner of the department of correction of the city of New York to appoint non-uniformed persons whose duties include overall security of the department of correction of the city of New York to positions of authority.