Gases do not behave as black bodies, as solids do, where they glow red hot. They emit light only at specific frequencies, which is called their spectrum. Yellow flames are caused by glowing soot particles (solid carbon). Hydrogen flames are not visible.
As Ed said, mold lubricant (oil) gets vaporized by the high temperature. When the high temperature vapor contacts air it condenses to small droplets that appear to be smoke. This smoke is very flammable.