"I'm givin' her all that she's got captain!"

That may be a quote from a Star Trek character, but it also could be used to describe America's refinery business. With almost all Gulf Coast refiners at maximum capacity, some companies like Valero (NYSE:VLO) are looking to ship crude from there to other facilities. Major companies like ExxonMobil (NYSE:XOM) and Phillips 66 (NYSE:PSX) have seen downstream margins expanding. Will they leave that cash in the segment and use it for expansion?

Today, Fool.com contributor Tyler Crowe checks in with the refining business in the U.S. and explains how a lack of investment in the industry could spell trouble down the road.