30 CFR § 19.11
How approvals are granted.
(a) All approvals are granted by official letter from MSHA. A lamp
will be approved under this part only when the testing engineers judge that
the lamp has met the requirements of the part and MSHA's records concerning
the lamp are complete, including drawings from the manufacturer that show the
lamp as it is to be commercially made. No verbal reports of MSHA's decisions,
concerning the investigation will be given, and no informal approvals will be
granted.
(b) As soon as the manufacturer has received the formal approval he
shall be free to advertise his lamps as permissible.
[Sched. 6D, 4 FR 4003, Sept. 21, 1939, as amended by Supp. 1, 20 FR 2718,
Apr. 23, 1955]