Conn. Gen. Stat. § 31-29: Manufacturing license for residential buildings.

No person, except a member of the immediate family residing in a dwelling house, tenement house, rooming house, apartment house or other residential building, and no firm, partnership or corporation shall use such building, in whole or in part, for the manufacture of any products, or parts thereof, until the owner thereof has obtained from the Labor Commissioner a license authorizing its use for such purpose. Said commissioner shall, before granting such license, establish the fact, by thorough inspection, that the building conforms in every respect to the requirements of the general statutes relating to heat, light, safety, health, ventilation and sanitation. The fee for such inspection, which shall accompany such application, shall be twenty-five dollars, payable, whether a license is granted or not, to the Labor Department.