(a) A registered nurse shall be assigned to each District of Columbia (“District”) elementary and secondary public and public charter school a minimum of 12 hours per week during each semester and during summer school if a summer school program is operated.

(b)(1) The minimum hours per week of registered nurse services at each school shall increase from 12 to 16 hours per week beginning 1 year after December 10, 1987. The minimum hours per week of registered nurse services at each school shall increase from 16 to 20 hours per week beginning 2 years after December 10, 1987.

• (2) Licensed practical nurses may be used to supplement the registered nurse work force in meeting the required 20 hours per week minimum registered nurse services at each elementary and middle school. The licensed practical nurses shall perform their duties under the appropriate supervision and in general collaboration with the registered nurses.