UPDATE: Chemical Fire Forces Evacuation in Midland June 29, 2012 at 8:15 PM CDT - Updated June 27 at 9:51 AM Staff Report NewsWest 9 MIDLAND COUNTY - a chemical fire in Midland County continues to burn at a business. The blaze erupted at Chemplex on Highway 158 and I-20. The blaze started around 2:45 Friday afternoon at the chemical plant. Two large 27,000 pound containers caught fire. One was holding ammonium persulfate and the other was holding sodium persulfate. Those chemicals are used to break down fracking fluids. We're told these chemicals catch fire easily and the heat outside mixed with the moisture in the container caused them to combust. Workers at Chemplex were quickly evacuated Officials say there are three more containers with the same ingredients so they're trying to contain the fire before those also combust. No one has been hurt in the blaze.