Water bottle cleaning instructions on a free bookmark could cause the creation of chlorine gas under certain conditions, according to a warning from the Windsor-Essex County Health Unit.

An alert posted to their website explains the Take Charge Windsor-Essex Choose Water bookmark could cause the "creation of, and exposure to, gas containing chlorine."

Possible ill effects include eye irritation and minor throat irritation or coughing.

Windsor-Essex County Health Unit

Bleach needs to be diluted in water or could cause a chemical reaction, according to the WECHU. (Windsor-Essex County Health Unit )

The health unit said there have been no reported reactions to the faulty instructions yet and asks anyone with one of the bookmarks to throw it out.

Proper water bottle cleaning instructions:

  • Use hot soapy water and rinse
  • Add 2.5 ml of household bleach for every one litre of water to disinfect
  • Pull the bottle from the solution after 45 seconds and rinse well 

-Source: WECHU