One of the standard designations for hazardous materials, indicating that ingestion causes fever. An example of a substance with this designation is sodium nitrate. Part of the Gefahrstoffverordnung (GefstoffV) safety system.
In more casual use, pyrogenic is sometimes employed as a synonym of (in)flammable, especially when something can generate flames or heat, such as matches or magnesium. Such things are some of the favorite toys of pyromaniacs.