What does insulation smell like burning?

When insulation burns, it typically emits a distinct and unpleasant odor, often described as a combination of plastic and chemical fumes. This smell can be acrid and irritating, similar to burnt rubber or electrical wiring. The specific scent may vary depending on the type of insulation material, such as fiberglass or foam, but it's generally a sign of potentially hazardous smoke and should be taken seriously. If you notice this odor, it's important to investigate the source immediately for safety.