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Waste Disposal

Waste is considered hazardous if: 
1.  It is on either of two lists of specific chemical substances developed by the Federal Environmental Protection Agency (EPA). Most commonly used organic solvents (e.g. acetone, methanol, toluene, xylene, methylene chloride etc.) are
included. 
2.  It is on a list of nonspecific sources that includes a broad range of spent halogenated and non-halogenated solvents. 
3.  It is on a list of specific sources that includes primarily industrial processes. 
4.  It exhibits any of the following characteristics as defined by the EPA. 
-   Ignitable
    A liquid with a flash point less than 60oC not a liquid and capable under normal conditions of causing fire through friction, absorption of moisture or spontaneous chemical changes an ignitable compressed gas an oxidizer. 
-  Corrosive
    It is aqueous and has a pH 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 0.25 inches per year at 55oC. 
-  Reactive 
   It is normally unstable, reacts violently with water, forms potentially explosive mixtures with water, generates toxic gases, vapors or fumes when mixed with water cyanide or sulfide wastes that generate toxic gases, vapors or fumes at pH conditions between 2 and 12.5. It is capable of detonation or explosive decomposition if subjected to strong initiation or under standard temperature and pressure. 
-  Toxicity Characteristic
   If an extract of the waste is found to contain certain metals, pesticides or selected organics above specified levels. 

Packaging Chemical Wastes

Materials that are to be disposed of as hazardous waste should be placed in containers of one gallon or less, with adequate closures. Corks or parafilm are not considered adequate. Often the original container is perfectly acceptable. Containers must be kept closed except during actual transfers. The container should not react with the waste being stored (e.g. no hydrofluoric acid in glass). 
Similar wastes may be mixed if they are compatible (e.g. flammable liquids). 
Whenever possible, wastes from incompatible hazard classes should not be mixed (e.g. flammables with oxidizers). Certain metals also cause disposal problems when mixed with flammable liquids or other organic liquids. Waste disposal cost is based on volume, not weight, therefore whenever possible containers should be filled, leaving a headspace for expansion of the contents.  Empty containers can be placed in the trash. If the original contents were highly toxic the container should be rinsed first with an appropriate solvent and the washings disposed of as hazardous waste. 

Labeling of Chemical Waste Containers

Waste containers must be labeled with the words HAZARDOUS WASTE along with the names of the principal chemical constituents and the approximate percentage.  Do not list reactants, only products. Use IUPAC or common names not symbols, structural diagrams or product trade names.  Labeling should be accurate and legible and should include the name of the generator and an extension where someone who is knowledgeable about that specific waste can be reached on the day of the pickup in case questions arise during packaging for
disposal.