From the Wikipedia page on PEX (Cross-linked polyethylene) > It is also used for natural gas and _offshore oil applications_, chemical transportation, and tran

From the Wikipedia page on PEX (Cross-linked polyethylene) > It is also used for natural gas and _offshore oil applications_, chemical transportation, and transportation of sewage and slurries. So yeah, a bacteria capable of dissolving that shouldn't be released anywhere near an offshore oil pipeline.