It should be noted that the Code of Federal Regulations should be investigated for any exceptions and exemptions and for specific waste names. A solid waste is defined in 40 CFR §261.2 as:

A solid waste is any discarded material that is not excluded under §261.4(a) or by a variance or non- waste determination

This definition includes gases, liquids, sludge, solid, refuse, or any other discarded materials. Solid waste is then further defined as hazardous waste using two different mechanisms:

By listing certain specific solid wastes as hazardous (i.e., wastes from certain industrial processes or sources). Listed wastes include (40 C.F.R. §§ 261.31-261.33):

• Non-specified/solvents (F-list)
  
  
• Originating from specific processes (K-list)
  
  
• Acute hazardous wastes/commercial chemical products (P-list)
  
  
• Toxic wastes/commercial chemical products (U-list)
  
  

By identifying characteristics (i.e., physical or chemical properties) which, when exhibited by a solid waste, make it hazardous. Characteristic wastes include (40 C.F.R. §§ 261.21-261.24):

• Ignitable (D001)
  
  
• Corrosive (D002)
  
  
• Reactive (D003)
  
  
• Toxic (D004)

Making this determination is a complex task that is a central component of the hazardous waste management regulations. The Code of Federal Regulations under Title 40 should be investigated for any exceptions and exemptions and for specific information.