Conn. Gen. Stat. § 7-438

(b) If a member is retired under this part and again accepts employment from the same municipality from which he or she was retired or any other participating municipality, he or she shall be eligible to participate, and shall be entitled to credit, in the municipal employees' retirement system for the period of such municipal employment. Such member shall receive no retirement allowance while so employed except if (1) such employment is for less than twenty hours per week, (2) his or her services are rendered for not more than ninety working days in any one calendar year, provided any member reemployed for a period of more than ninety working days in one calendar year shall reimburse the Municipal Employees' Retirement Fund for retirement income payments received during such ninety working days, or (3) such member does not participate in the municipal employees' retirement system during the period of his or her reemployment.

(c) Notwithstanding the provisions of subsections (a) and (b) of this section, if a uniformed member of a paid municipal fire department or regular member of a paid municipal police department is retired under this part and subsequently accepts employment in a public safety position from any school district or regional school district, which district is a participating municipality, he or she shall continue to receive his or her retirement allowance while so subsequently employed, but he or she shall not be eligible to further participate or be entitled to additional credit in the municipal employees' retirement system for the period of such subsequent employment.

Subsection (b) may be reasonably understood to embody a judgment that a participating municipality should not have to contribute additional funds to a member's retirement pension while at the same time paying his salary. 326 C. 160.