No person may install, repair, or close a tank system after July 9, 1990, unless:
a supervisor certified in the appropriate discipline is physically present on site at all critical junctures during the storage tank project; and
the certified supervisor in item A is also a certified contractor or is in the employ of a certified contractor.
A copy of the contractor's current certificate must be at the work location and posted in a conspicuous place. Certified supervisors must have copies of current certificates issued by the agency at the location where they are supervising work.
Owners or operators of an underground storage tank must not allow a storage tank project to be performed on their tank system, except in compliance with subpart 1.
MS s 116.491
14 SR 1718
October 2, 2007