Chemical heat

I pass a chemical plant each morning when driving to work. This morning (it was still almost dark) the sky was lit orange above the plant, they were burning the contents of a chemical installation. They do that in case of an calamity, or when they are cleaning the Process installations for mojor maintenace. Anyway, it's a terrific sight, the flames are 10 meters high, and make a roaring noise.
So I stopped at a parking lot and sketched the scene looking trough the windshield of my car. then I drove on to the office. Took me about 20 minutes.