Oil producer BP PLC (NYSE: BP) complained to Canada’s National Energy Board (NEB) regulator about Enbridge Inc.’s (NYSE: ENB) implementation and then abrupt reversal of new rules for shipping crude on its Mainline pipeline system, NEB documents showed on June 7.

Enbridge notified shippers last month that it would introduce a supply verification procedure to determine each company’s volumes on the Mainline but scrapped the policy on June 4.