Special management waste is waste resulting from production processes that, due to its characteristics, is not qualified as hazardous (corrosive, reactive, explosive, toxic, flammable, and biological-infectious materials, jointly referred to as CRETIB, in Spanish)

  • Cardboard
  • Paper
  • Plastic
  • Wood
  • Textile waste (uncontaminated)
  • Rubber
  • Glass


    1. Steel
    2. Aluminum
    3. Copper
    4. Bronze
    5. Cast iron
    6. Scrap of various types
    7. Burrs
    8. Slag


Hazardous waste means non-recyclable waste or waste classified as dangerous due to its intrinsic properties, which poses risks to health or the environment.

The CRETIB code refers to the characteristics by which waste is considered as hazardous. When exhibiting at least one of such characteristics waste is classified as hazardous. Furthermore, non-hazardous waste mixed with hazardous waste is contaminated becoming thus hazardous.

In Mexico, the NOM-052-SEMARNAT-1993 standard defines CRETIB as:

“The classification code for the characteristics exhibited by hazardous waste, referred to as corrosive, reactive, explosive, toxic, flammable, and biological- infectious.”  

The most appropriate name for such standard is CRETIB.

Countries are free to organize their laws according to their particular needs and regulatory frameworks, without contravening international agreements such as the Basel Convention.  

According to the NOM-052-SEMARNAT-2005 standard, materials may exhibit one or more characteristics defined by the CRETIB code, which stands for:

  • C: Corrosive, which refers to the ability of certain compounds to dissolve another compound.
  • R: Reactive, which characterizes hazardous waste that is unstable and may pose an explosion hazard in a certain stage within the waste management cycle.
  • E: Explosive, which is the ability of certain chemical substances to provoke an explosive or detonating decomposition or reaction, whether alone or in the presence of a source of energy, or if heated when confined. Explosiveness should not be determined by a laboratory test, but based on the knowledge of the waste origin or composition.
  • T: Toxic, which refers to the ability of certain substances to damage living tissues and the central nervous system, to provoke a serious illness or, in extreme cases, to cause death, when ingested, inhaled, or absorbed through the skin.


recoleccion de residuos peligrosos


The characteristic of a certain substance or mixture of substances that results in an ecological imbalance


The extent to which a certain substance or mixture of substances may damage or cause death to an organism in a short period of time or by a single exposure.  


The property by which a certain substance or mixture of substances may have long-term detrimental effects on organisms, generally from continuous or repeated exposure, being able to result in carcinogenic, teratogenic, or mutagenic effects.

  • I: Flammable, which means the extent to which a gas, liquid, or solid may ignite and the speed at which, once ignited, it may propagate its flames. The faster the ignition, the more flammable the material. Liquids are not flammable by themselves, but because their vapors are ignitable.
  • B: Biological-Infectious. Biological-infectious waste contains bacteria, viruses, or other microorganisms able to infect. Such waste contains toxins produced by microorganisms able to provoke infections.

Each of such properties can be specifically tested at the laboratory under standard conditions in order to detect them on the substances under test.


  • Waste lube oils
  • Contaminated water
  • Ballasts
  • Used batteries
  • Toner cartridges
  • Personal protection equipment
  • Contaminated packages and/or containers
  • Contaminated tows and gloves
  • Used filters
  • Fluorescent lamps
  • Industrial ink cans
  • Bins for used and expired aerosols
  • Contaminated liquids
  • Contaminated sludge
  • Expired drugs
  • Batteries
  • Expired paint
  • Expired chemicals
  • Metal burr
  • Contaminated auto parts and spare parts​
  • Residues with solvents
  • Contaminated coating residues
  • Contaminated resins
  • Contaminated and/or expired developing solutions and fixers
  • Contaminated silica sand
  • Solvents
  • Chromic solutions
  • Contaminated solids
  • Contaminated soil
  • Among others


Urban Solid Waste (RSU, in Spanish) or urban waste is non-gaseous and non-liquid waste generated in urban centers or in their influence areas: Private homes, shops, offices, and other facilities. Urban solid waste does not comprise hazardous waste, although it may be produced in such places or activities. Most urban solid waste generated in a community is considered as household waste.
  • Organic matter
    1. Residues from food processing or cleaning activities
    2. Food leftovers
    3. Yard trimmings
  • Paper and Cardboard
    1. Newspapers
    2. Magazines
    3. Advertising materials
    4. Boxes
    5. Packing materials
  • Plastics
    1. Bottles
    2. Bags
    3. Packing materials
    4. Bricks and tetrabricks
    5. Disposable plates, cups, and cutlery
    6. Metals such as cans or pots
  • Glassware
    1. Bottles
    2. Jars
    3. Broken glass tableware

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