MA Gen L ch 146 § 49 (2021)
2021 Massachusetts General Laws|Part I - Administration of the Government|Title XX - Public Safety and Good Order|Chapter 146 - Inspection of Boilers, Air Tanks, Etc. Licenses of Engineers, Firemen, and Operators of Hoisting Machinery|Section 49 - Classes of Licenses and Work Permitted; License Renewal; Continuing Education

Section 49. Licenses shall be granted according to the competence of the applicant and shall be classified as follows: Engineer's licenses: First class, to have charge of and operate any steam plant. Second class, to have charge of and operate a boiler or boilers, and to have charge of and operate engines, no one of which shall exceed 150 horsepower, or to operate a first class plant under the engineer in direct charge thereof. Third class, to have charge of and operate a boiler or boilers not exceeding, in the aggregate, 150 horsepower when solid fuel is burned or not exceeding, in the aggregate, 500 horsepower when steam is generated by the use of liquid or gaseous fuel, electric or atomic energy or any other source of heat and an engine or engines not exceeding 50 horsepower each or to operate a second class plant under the engineer in direct charge thereof. Firemen's licenses: First class, to have charge of and operate any boiler or boilers where the safety valve or valves are set to blow at a pressure not exceeding 25 pounds to the square inch or to operate high pressure boilers under the engineer or fireman in direct charge thereof. No engineer or fireman in charge of a steam plant shall be permitted to be in charge of any other steam plant, unless it is within one mile from the specific plant of which the engineer or fireman is designated to be in charge or unless a licensed second or third class engineer or fireman shall be in attendance at such plant and shall perform his duties under the supervision of such engineer or fireman. Second class, to operate any boiler or boilers under the engineer or fireman in direct charge thereof. A person holding a first class fireman's license may operate a third class plant under the engineer in direct charge thereof. Special licenses: A person who desires to have charge of or to operate a particular steam plant may, if he files with his application for such examination a written request signed by the owner or user of the plant, be examined as to his competence for such service and no other and, if found competent and trustworthy, shall be granted a license for such service, and no other; provided, however, that no special license shall be granted to give a person charge of or permission to operate an engine over 50 horsepower, or a boiler or boilers exceeding, in the aggregate, 250 horsepower, except that where the main power plant is run exclusively by waterpower, developed on the premises of such plant a major part of the year and has auxiliary steam power for use during the periods of low water, a special license may be granted to an applicant holding an engineer's license.  The department shall promulgate regulations which shall require the renewal of such licenses every five years. Individuals licensed to operate boilers under a special license shall demonstrate completion of 6 hours of continuing education at or through an institution or organization approved by the state fire marshal, in consultation with the chief inspector, during each 5–year period preceding each license renewal. All other individuals licensed to operate boilers shall demonstrate the completion of 30 hours of continuing education before each license renewal.