Spending hundreds of millions to billions of dollars simply to maintain growth is a key characteristic of much of the energy and materials space. Due to shareholder expectations, companies that aren't generating cash from operations typically turn to debt or equity sales. Each of the four companies discussed in the video below has driven up its debt levels to heights that worry Motley Fool analyst Taylor Muckerman.

Two companies on the wrong side of the fence
Of the four companies, two materials companies worry him the most. AK Steel (NYSE:AKS) is trying to survive in the maligned United States steel industry, and Berry Plastics (NYSE:BERY) is finding it tough to overcome interest expenses stemming from acquisition-related debt. Both of these companies need to figure out a way to right their ship, and quickly.

Will a natural gas rebound bail these producers out?
Two natural gas prices also "passed" Taylor's screen, and he believes they have a chance to rebound along with natural gas prices. Writedowns in 2012 forced Ultra Petroleum (NASDAQ:UPL) and Quicksilver Resources (NASDAQOTH:KWKAQ) into precarious situations, but with prices climbing, these companies should be fine.