• To lessen the risks that improper used oil disposal poses to the environment.
• To reduce waste, encourage the recycling and repurposing of used oils into new goods like base oils or lubricants.
• To guarantee that producers, consumers, and recyclers bear accountability for the environmentally responsible handling of used oils.
  
  Used oil is categorized based on its origin, composition, and the way it has been used. Understanding these categories helps in determining the proper management, recycling, or disposal methods. Broadly, used oil is classified into two main categories:
  1. Used Lubricating Oil (ULO):

This is the most common category of used oil and includes oils that are used to lubricate engines, machinery, and various mechanical systems. Over time, these oils degrade due to contaminants such as dirt, water, and metal particles.

Subcategories of Used Lubricating Oil:

• Engine Oil: Used in internal combustion engines of vehicles, machinery, and generators.
• Transmission Oil: Used in gearboxes, transmissions, and other mechanical systems.
• Hydraulic Oil: Used in hydraulic systems such as lifts, presses, and construction machinery.
• Compressor Oil: Used in compressors for cooling and lubrication.
• Industrial Lubricants: Oils used in industrial machinery for lubrication.

2. Used Transformer Oil:

Electrical transformers, capacitors, and other electrical devices use this kind of oil as an insulating and cooling medium. Transformer oils, which cool the system and stop electrical discharges, are usually synthetic or mineral-based oils. Transformer oils deteriorate over time and can get polluted by several elements, including moisture and grime.

Subcategories of Used Transformer Oil:

• Mineral Oil: A petroleum-based oil used in transformers for insulation and cooling.
• Synthetic Oil: Used in transformers, usually in cases where extreme temperature resistance is needed.

3. Used Cooking Oil: 

Oils used in food processing and cooking fall under this category. After being used repeatedly for cooking or frying, these oils frequently degrade to the point that they are thrown out.

Subcategories of Used Cooking Oil:

• Vegetable Oil: Oils such as soybean, canola, or palm oil that are commonly used in kitchens and restaurants.
• Animal Fats: Used fats from animal-based cooking processes, often derived from meats or poultry.

4. Used Industrial Oil:

Oils utilized in industrial processes other than lubrication, like processing and manufacturing, fall under this category. They can be tainted with chemicals, metals, or other materials and are usually oils used for particular activities, such metalworking.

Subcategories of Used Industrial Oil:

• Cutting Oils: Oils used in metalworking and machining operations to reduce friction and heat.
• Quenching Oils: Oils used in heat treatments, especially in steel production and metal industries.
• Rolling Oils: Oils used in rolling mills in the steel industry for lubrication and cooling.

• 5. Used Fuel Oil:

  This type of oil is typically used in engines and industrial boilers as a fuel source. Used fuel oil is generated from industrial operations, power plants, and shipping.

  Subcategories of Used Fuel Oil:

• Diesel Oil: Used diesel oil from engines, particularly from vehicles, trucks, and heavy machinery.
• Heavy Fuel Oil: Used oils from large engines, power plants, and shipping industries.