BP's expected settlement with the U.S. Department of Justice and the Securities and Exchange Commission over the 2010 Deepwater Horizon disaster in the Gulf of Mexico would mark another step down the road to resolving the liabilities from the 2010 explosion…But even if many outstanding questions about the ultimate financial hit on BP are answered…Thursday, other big ones remain unresolved. Crucially, the potential settlement with the DoJ and the SEC doesn’t include environmental penalties…BP could be liable for a maximum penalty of $5.4 billion under the Clean Water Act, rising to as much as $21 billion if the company is found to be grossly negligent, which it has denied.