49 CFR § 392.67
Heater, flame-producing; on commercial motor vehicle in motion
November 18, 2020
No open flame heater used in the loading or unloading of the commodity transported shall be in operation while the commercial motor vehicle is in motion.
[33 FR 19732, Dec. 25, 1968, as amended at 60 FR 38747, July 28, 1995]