46 CFR §153.1025

1. (a)No person may load or carry any other cargo in a containment system approved for motor fuel antiknock compounds containing lead alkyls except a cargo to be used solely in the manufacture of motor fuel antiknock compounds.
2. (b)The master shall ensure that no person enter a pumproom or void space that contains piping from a containment system approved for motor fuel antiknock compounds containing lead alkyls unless:
   1. (1)The pumproom or void space atmosphere has been analyzed for its lead (as Pb) content and found to be less than 0.075 mg/m 3; or
   2. (2)The person follows the procedures for entering a cargo tank described in paragraph (c) of this section.
3. (c)No person may enter a cargo tank endorsed for motor fuel antiknock compounds containing lead alkyls without prior specific authorization from the Commandant (CG-ENG). This authorization may be obtained by calling telephone number 202-372-1420 or e-mail hazmatstandards@uscg.mil if the person has previously obtained approval for the cargo tank entry procedure from the Commandant (CG-ENG).
4. (d)No person may enter a cargo tank endorsed for motor fuel antiknock compounds if he does not follow the conditions in the authorization under paragraph (c) of this section.