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Researcher Exposed by Confusing Ethanol with Formalin

What Happened?

A researcher attempted to make a stock solution of 70% ethanol but used 10% formalin instead of 100% ethanol. The researcher filled a spray bottle and took it home to use as a disinfectant, leaving the remaining solution in the lab labeled “70% ethanol”. 

The researcher used the formalin solution at home as a disinfectant for their hands and belongings due to concerns related to COVID-19.

A different researcher in the lab wiped down a biosafety cabinet, experimental equipment, and gloved hands with the “70% ethanol”-labeled formalin solution to prepare for a routine experiment. This researcher paused their experiment because of mild irritation and the odd smell of the solution and notified their PI and lab mates.

The discovery was made that the labeled stock solution was not 70% ethanol and that it instead contained formalin.


What Was The Cause?

The immediate cause was that the researcher who made the solution did not recognize the hazard. The lab’s 10% formalin container looked very similar to that of 100% ethanol, and the researcher did not read the labels before preparing the dilution. The root cause was likely a lack of knowledge about hazards in the laboratory. Furthermore, the researcher did not have an awareness of associated risks when chemicals from the laboratory are taken home.

How Can Incidents Like This Be Prevented?

  • Always double-check container labels when preparing solutions. Also, look at the GHS symbol.
  • Never take lab chemicals home. Do not repurpose chemicals from the lab for personal use.


When in doubt, pause work and seek advice to resolve uncertainties and conflicts.

The researcher who discovered the error stopped work and reported problems to their lab mates and PI immediately, this was a commendable course of action.

Take the time to consider how your actions and decisions can affect you and others now and in the future.


Formalin is an aqueous solution of formaldehyde. Formalin is used as a disinfectant and as a fixative for histology or to preserve biological specimens.


  • Highly flammable
  • Acutely toxic
  • Probable human carcinogen and reproductive toxin
  • Eye, skin, and respiratory tract irritant
  • Environmental toxin
  • Exudes a pungent smell

Quick Action Tips

If exposed to formaldehyde:

  • Inhalation: Fresh air, call physician
  • Eye or skin: Remove contacts/clothing and rinse extensively for at least 15 min, call physician
  • Inform your PI



> Formalin SDS

> CDC Medical Management Guidelines for Formaldehyde 

> Formaldehyde PubChem