"Polyethylene rollout waste containers often are provided by trash haulers as a service to commercial building tenants. Intended primarily for outdoor use, these containers may find their way into the structures' interior. Almost all of these inexpensive polyethylene containers have excellent weather-resistance and durability for exterior storage, but represent a huge fuel load when moved indoors. An individual polyethylene container has a latent heat potential of about 20,020 Btu/pound (4.6 MJ/kilogram). A typical 50-gallon (0.189 m3) rollout waste container weighs 10 to 13 pounds (4.5 to 5.9 kg). In that weight range, the container alone adds from 200,200 to 260,260 Btu (211 MJ to 275 MJ) to a room."
Coffee Break Training - Fire Protection Series No. 2008-8
United States Fire Administration: http://www.usfa.fema.gov/