Hundreds of gallons of xylenes are used each year in pathology laboratories as a part of the process of staining cells for microscopy work, so that healthy and diseased cells are easier to identify. Xylenes are also used as solvents in some applications because they are less volatile than acetone.
Xylenes are also toxic and flammable, so they qualify as hazardous waste when no longer needed.
Xylene distillation and reuse
Instead of shipping used xylenes off campus for incineration, we collect and distill the used xylenes in our EH&S facility. Most of the xylenes we bring to our facilities are mixed with paraffin and ethanol. The boiling point of ethanol is about 78 degrees C while the boiling points of xylenes are roughly 140 C. Paraffin and dyes do not boil. The distilled xylenes are of very high purity and can be used again and again as solvents and in pathology procedures. We sell these xylenes back to the campus community, either in five gallon carboys or one gallon bottles.
We distill and resell about 500 gallons of xylene a year. Most of the xylene is resold to pathology laboratories at the UW Medical Center.
We save the UW on average about $10,000 a year in avoided costs of hazardous waste disposal and procurement of new xylene with this program.
How to buy used xylenes
If you would like to purchase 5 gallon carboys of xylenes or request an empty carboy or bottle collection, please email EH&S at email@example.com.