http://www.gulfweb.org/bigdoc/report/appgb.html
It has a flammability rating of 1, not too flammable. That does not mean you couldn’t mix it with NaPalm, but what the article is describing does not sound like chemical weapons.
I was thinking shredded magnesium——easy to ignite, tough to put out, and readily available. All they needed to do was grind up a bunch of metal ladders or old aircraft skin.