International Harvester (HR) which changed its name to Navistar (NAV) in February of 2007 was in the Dow Jones from 1925-1991. It had a lot of financial problems, but did not go BK while in the DJI. It still trades on the bulletin-board "pink" sheets as NAVZ. Was frought with all sorts of inaccuracies in their accounting and issues with auditors and delisted.
Texaco lost a $10 billion lawsuit vs. Penzoil. Around 1985. Filed for bankruptcy in 1987 or so. I don't remember the reason for the lawsuit.
It is very simple, Oil co's go outa business because they don't run their companies well. A oil company, who leverages, buy's up lease rights far faster than what they pull outa the ground combined with locking in Steel Prices at to high of levels, ontop of drilling dry holes, on top of "Costly" projects such a Shale drilling, on top of a Oil company that is Traded on the Markets getting shorted, taking away from its "Capital". The price of oil at 100 level had oil companies get crazy and expand their "leverage". Chespk is an example. They are selling off projects that they locked in but have yet to drill, for less than what they paid. land Leases went through the roof for the first few quarters. Oil has pulled back. Plenty of reason's why Oil Companies can go under.