30 CFR § 57.4230
Surface self-propelled equipment.
(a)(1) Whenever a fire or its effects could impede escape from
self-propelled equipment, a fire extinguisher shall be on the equipment.
(2) Whenever a fire or its effects would not impede escape
from the equipment but could affect the escape of other persons in the area,
a fire extinguisher shall be on the equipment or within 100 feet of the
equipment.
(b) A fire suppression system may be used as an alternative to fire
extinguishers if the system can be manually activated.
(c) Fire extinguishers or fire suppression systems shall be of a type
and size that can extinguish fires of any class in their early stages which
could originate from the equipment's inherent fire hazards. Fire
extinguishers or manual actuators for the suppression system shall be located
to permit their use by persons whose escape could be impeded by fire.