Original sentence: "  Those elements as residues, as well as high temperatures sustained in the rubble, can result from burning thermate.Jones believes the sulfur is a result of deliberate demolition using thermate, while NIST notes that the metals were abundant in the constructions of the towers, and much sulfur was present in the drywalls which were composed of calcium sulfate.No clear explanation for the source of the sulfur has been identified.Samples of a once molten mixture of iron, aluminum, and sulfur were found in the rubble and analyzed by FEMA, who was unable to determine the source of the sulfur stating: "The severe corrosion and subsequent erosion of Samples 1 [WTC7] and 2 [Towers] are a very unusual event
Edited sentence: Jones believes the sulfur is a result of deliberate demolition using thermite, while NIST notes that the metals were abundant in the constructions of the towers, and much sulfur was present in the drywalls which were composed of calcium sulfate.Samples of a once molten mixture of iron, aluminum, and sulfur were found in the rubble