A hopper car is a covered- or open-top hopper railcar designed to force product out of a hopper using air pressure. They have distinct funnel shaped bottom outlets that may be visible from a distance. It is designed for bulk commodities such as coal, ore, cement, and solid granular materials. Hazardous materials shipped in these can include toxic and oxidizing materials in the form of pesticides and fertilizers. Note: Although a hopper car may not be transporting hazardous materials, perishable food products such as grain may be treated with a fumigant to prevent decay. In these situations a hopper car may contain a toxic hazard even though the material itself is unregulated.