SECTION 2. Limitations

(a) Operating under the influence. This chapter does not amend existing penalties for operating, navigating or being in actual physical control of any motor vehicle, train, aircraft, motorboat or other motorized form of transport or machinery while impaired by marijuana or a marijuana product or for consuming marijuana while operating, navigating or being in actual physical control of any motor vehicle, train, aircraft, motorboat or other motorized form of transport or machinery.

(b) Transfer to or possession by a person under 21 years of age. This chapter shall not be construed to permit the knowing transfer of marijuana, marijuana products or marijuana accessories, with or without remuneration, to a person under 21 years of age or to allow a person under 21 years of age to possess, use, purchase, obtain, cultivate, process, manufacture, deliver or sell or otherwise transfer marijuana or marijuana accessories.

(c) Manufacture of products. Unless done pursuant to a marijuana product manufacturer license issued by the commission, this chapter does not authorize a person to manufacture marijuana or hemp by means of any liquid or gas, other than alcohol, that has a flashpoint below 100 degrees Fahrenheit.

(d) Property. This chapter shall not be construed to:

(1) prevent a person from prohibiting or otherwise regulating the consumption, display, production, processing, manufacture or sale of marijuana and marijuana accessories on or in property the person owns, occupies or manages, except that a lease agreement shall not prohibit a tenant from consuming marijuana by means other than smoking on or in property in which the tenant resides unless failing to do so would cause the landlord to violate a federal law or regulation;

(2) prevent the commonwealth, a subdivision thereof or local government agency from prohibiting or otherwise regulating the possession or consumption of marijuana or marijuana accessories within a building owned, leased or occupied by the commonwealth, a political subdivision of the commonwealth or an agency of the commonwealth or a political subdivision of the commonwealth; or

(3) authorize the possession or consumption of marijuana or marijuana accessories on the grounds of or within a public or private school where children attend classes in preschool programs, kindergarten programs or grades 1 to 12, inclusive, on a school bus, in any youth center, or on the grounds of or within any correctional facility or detoxification facility.

(e) Employment. This chapter shall not require an employer to permit or accommodate conduct otherwise allowed by this chapter in the workplace and shall not affect the authority of employers to enact and enforce workplace policies restricting the consumption of marijuana by employees.

(f) Negligent conduct. This chapter shall not amend existing penalties for conduct involving the performance of any task while impaired by marijuana that would constitute negligence or professional malpractice and shall not prevent the imposition of any civil, criminal or other penalty for such conduct.

(g) Relation to medical use of marijuana. This chapter shall not be construed to affect the provisions of chapter 369 of the acts of 2012, relating to the medical use of marijuana as enacted by the people in the state election in 2012 except where otherwise provided for in this chapter.

(h) Adulteration and misbranding. This chapter shall not exempt marijuana or marijuana products from sections 186 to 195, inclusive, of chapter 94 of the General Laws, relating to the adulteration and misbranding of food, drugs and various articles. Marijuana included in a marijuana product manufactured in compliance with the regulations under this chapter shall not be considered an adulterant.