Section 57.5065 - Fueling practices(a) Diesel fuel used to power equipment in underground areas must not have a sulfur content greater than 0.05 percent. The operator must retain purchase records that demonstrate compliance with this requirement for one year after the date of purchase.(b) The operator must only use fuel additives registered by the U.S. Environmental Protection Agency in diesel powered equipment operated in underground areas. 66 FR 5907 , Jan. 19, 2001; 66 FR 35520 , July 5, 2001