Environmental activism is perhaps the greatest threat to PBF. Make no mistake about it, a far left administration willing to use Executive Order for political agenda could take a good fundamentally valued investment like PBF and really harm the company.
Environmental regulations have and will continue to increase the cost for refineries to operate in this country, but it is applied to all the refineries, not just PBF. What you want to worry is that 2 of the PBF's 3 refineries are located in the east coast where refineries can hardly make much profits (several have been either closed or sold in the recent few years). The Ohio refinery is capable to process heavy Canadian crude oil and should be making good profit though.
Blackstone seems smart again that it recently sold most of the shares it holded at $28 per share!!!