SECTION 1. Section 91 of chapter 32 of the general laws, as appearing in the 2008 Official Edition, is hereby amended by striking subsection (e) and inserting in place thereof the following subsection:-

“(e) Notwithstanding the provisions of paragraphs (a) to (d), inclusive, in any period during which there is a critical shortage of certified teachers available for employment in a school district, said school district may employ as a teacher or as a mentor to other teachers any person who has retired from the state employees’ retirement system, the teachers’ retirement system and all county, city and town contributory retirement systems, established under the provisions of this chapter.  Any such retired person who renders service in a public school district as a teacher or mentor to other teachers shall be subject to all laws, rules and regulations governing the employment of teachers in the school district.  Such persons shall not be deemed to have resumed active membership in their respective retirement system and said service shall not be counted as creditable service toward retirement; but in the first two years immediately following the effective date of retirement, the earnings received by  a teacher  who retired pursuant to subdivision (4) of section 5 when added to any pension or retirement allowance he is receiving shall not exceed the salary that is being paid for the position from which he was retired or in which his employment was terminated."