Guidelines for Using Carboys

The University of Wisconsin-Madison’s Chemical Safety Disposal Group provides three types of carboys for the collection of used materials. Each carboy type has its own set of requirements, as described below. All carboys can be obtained by submitting an online request on the Chemical Disposal/Surplus Pickup Form webpage. When carboys are filled, or no longer needed, the same form is used to request the carboys be picked up.  

Flammable Solvent Waste Carboys

Carboys are five-gallon (20 liter) polypropylene plastic containers available free from the University of Wisconsin-Madison’s Chemical Safety Disposal Group for the collection of flammable solvent waste. They are delivered to your lab, and picked up from your lab, by submitting an online request.  

White carboys are used to collect flammable, non-halogenated solvents that are suitable for fuel blending, such as acetonitrile, ethyl acetate, hexane, methyl alcohol and toluene.  

Yellow/orange carboys are intended for highly halogenated solvents, or mixtures of solvents using more than 5% of a halogenated solventSome examples of halogenated solvents include but are not limited to methylene chloride, chloroform, and trichloroethylene.  

Both the halogenated and non-halogenated solvents will eventually be bulked and shipped for incineration through our hazardous waste vendor. The halogenated wastes must be incinerated specifically for destruction at 99.99% level (i.e., to carbon dioxide, water and hydrogen chloride) with scrubbing for hydrogen chloride, which is a more costly waste stream. 

If you added halogenated solvent to a nonhalogenated white carboy or container by mistake, just list what you have added to the container/carboy on your Chemical Inventory of Waste Flammable Solvents (Carboys) Form. 

The use of these carboys for Acids, Corrosives, Volatile Toxics, all Metals, and Oxidizing Chemicals is PROHIBITED without Chemical Safety Approval. Carboys submitted for a pickup containing other than an acceptable solvent may be subject to refusal of pickup. See below for examples.


  • Always keep the carboys closed except when adding solvent. This is a U.S. Environmental Protection Agency Regulation. 
  • Do not fill into the shoulder or neck of the carboy. 
  • Keep the amount of water in the carboys to a minimum. Too much water in the carboys can cause problems with incineration and adds to the cost of disposal. 
  • Do not put foul-smelling solvents containing malodorous components, such as mercaptans/thiols, directly into your solvent carboy.  
  • Track what you put into the carboys. This information will be needed for disposal. 
  • Do not put any solids or very viscous materials in the carboysthe carboys will be emptied by a pump. 
  • Do not move waste carboys. They must remain at or near the point of generation until picked up by EH&S. 
  • Keep the total carboys in a lab to a minimum- no more than 10 carboys can be in a lab space. 
  • Only request the carboys necessary for your work—too many carboys can clutter a lab space, increase the total amounts of flammables in a lab, or negatively impact lab’s MAQ. Smaller, disposable containers (e.g. empty solvent bottles) are permitted for solvent collection but will not be supplied. 
  • Do not put acids, such as nitric or sulfuric acids, strong bases, strongly oxidizing chemicals, water or air-reactive chemicals or polymerizable chemicals into solvent carboys. These can cause unanticipated reactions that can create toxic fumes or pressurize the carboys. 

To comply with EPA regulation, you must complete the Chemical Inventory of Waste Flammable Solvents (Carboys) form and provide a reasonable estimate of its contents. We must routinely analyze carboys to determine discrepancies between content and the information you report on this form. Please leave this form with the carboy when it is ready for Chemical Disposal Pickup. 

Below are specific examples of chemicals and chemical classes that should not be added to solvent carboys.  

If you have any questions regarding the disposal of waste solvents in carboys, contact Chemical Safety.  

Waste Silica Carboys 

The Chemical Safety Disposal Group will provide free 20L polypropylene plastic carboys for the collection of used silica. The intended use of these carboys is for the collection of silica gel, such as that used in chromatography. Silica gel that has been used with or may be contaminated with organic solvents is also allowed in these carboys.  

Please note, to prevent a harmful exposure to you or a spill, keep your carboy securely capped at all times, except when adding silica. This is a U.S. Environmental Protection Agency regulation. 

Avoid putting these following items into a Silica Carboy: 

  • Normal lab trash (gloves, weigh boats, paper, pipette tips, etc.)
  • Heavy metals (Hg, Cd, Pb, Cr, Se, Ba, As)
  • Sharps (needles, razors).
  • Lab glass (test tubes, small bottles, etc.).

 To comply with EPA regulation, you must complete the Chemical Inventory of Hazardous Waste Silica form and provide a reasonable estimate of its contents. We must routinely analyze carboys to determine discrepancies between content and the information you report on this form. Please leave this form with the carboy when it is ready for Chemical Disposal Pickup. 

Used Oil Carboys

The Chemical Safety Disposal Group will provide free 20 L polypropylene plastic carboys to be filled with used oil for recycling.  

You may use your own container, such as a five-gallon pail. It should be able to be completely sealed and leak-proof. The outside of the container must be kept clean and labeled as “Used Oil”.   

Acceptable types of used oil to be put into a carboy for disposal include Motor Oil, Fryer/Cooking Oil, Refrigeration Oil, Hydraulic and Vacuum System Oil.   

Please note, DO NOTDrain Transformer Oil into a carboy unless it directly states on the transformer that it is “PCB free”. If the Transformer Oil does not directly state that it is “PCB free”, the Chemical Safety Disposal Group should be notified, and this oil will need to be tested for PCB contamination. Label all Transformer Oil containers as “Used Transformer Oil”.   

Please do not fill these carboys with:  

  • Solvents  
  • Diesel Fuel  
  • Anti-Freeze  
  • Any Type of Chemical  
  • Water  

Request Chemical Pickup


Luke Hendricks
Phone: 608-209-5224

Tim Lanzhammer
Phone: 608-220-4273
Phone: 608-265-5700