Various: Canada’s oil sands producers face the prospect of a patchwork of costly climate regulations in their key U.S. markets as American states step up their efforts to adopt California-style low-carbon fuel standards. Dozens of states are moving ahead with regulations that would penalize more carbon-intensive fuels like those made from oil sands bitumen, and encourage the use of greener alternatives. The states are proceeding amid growing doubts about President Barack Obama’s ability to get …