5.2.1 Ignitability

• A liquid other than an aqueous solution containing less than 24 % alcohol by volume, having a flashpoint of less than 140°F.
• A non-liquid capable under standard temperature and pressure of causing fire through friction, spontaneous combustion, and when ignited, burns so vigorously and persistently that it creates a hazard.
• It is an ignitable compressed gas.
• It is an oxidizer.  

5.2.2 Corrosivity

• It is aqueous and has a pH of less than or equal to 2 or greater than or equal to 12.5.
• It is a liquid and corrodes steel at a rate greater than 0.250 inch per year.  

5.2.3 Reactivity

• It is normally unstable and readily undergoes violent change without detonating.
• It reacts violently or forms potentially explosive mixtures with water.
• When mixed with water, it generates toxic gases, vapors or fumes that present a danger to human health or the environment.
• It is a cyanide or sulfide bearing waste that can generate toxic gases vapors or fumes that present a danger to human health or the environment when exposed to pH conditions between 2 and 12.5.
• It can detonate or explode if subjected to a strong initiating source or if heated under confinement.
• It is readily capable of detonation or explosive decomposition or reaction at standard temperature and pressure.
• It is a forbidden explosive as defined in 49 CFR 173.

5.2.4 Toxicity

A solid waste exhibits the characteristic of toxicity if, using the EPA’s Toxicity Characteristic Leaching Procedure (TCLP) test method, the extract from a representative sample of the waste contains any of the contaminants listed in Table 1 of 40 CFR 261.24 at the concentration equal to or greater than the respective value given in the table. There are 40 contaminants listed in Table 1. Most of these are heavy metals, organic solvents, and pesticides.