49 CFR §227.205

1. (a)A railroad may not use a locomotive if it is part of an in-service freight train transporting a PIH material, including a residue of a PIH material, and the locomotive cab is occupied by an employee identified in § 227.201(a)(1)(i)(A) through (D) (subject employee), unless the locomotive cab has appropriate storage facilities to hold the number of EEBAs required to be provided.
2. (b)The storage facility for each required EEBA must—
   1. (1)Prevent deformation of the face piece and exhalation valve, where applicable;
   2. (2)Protect the EEBA from incidental damage, contamination, dust, sunlight, extreme temperatures, excessive moisture, and damaging chemicals;
   3. (3)Provide each subject employee located in the locomotive cab with ready access to the EEBA during an emergency; and
   4. (4)Provide a means for each subject employee to locate the EEBA under adverse conditions such as darkness or disorientation.
3. (c)A railroad must comply with the applicable manufacturer's instructions for storage of each required EEBA and must keep a copy of the instructions at its system headquarters for FRA inspection.