We use cookies to help us improve the website and your experience using it. You may delete and block all cookies from this site at any time. However, please note this may result in parts of the site no longer working correctly. If you continue without changing your settings we will assume you are happy to receive all cookies on this site.


Handling formalin

The department uses 10% neutral buffered Formalin (4% formaldehyde) and this should be handled with care at all times. We obtain our formalin from Genta, a reputable supplier and they have issued the following safety information:

10% Formalin

Acute Toxicity Category 4 - Harmful if inhaled
Skin Sensitizer Category 1 - May cause an allergic reaction
Carcinogen Category 1B - May cause cancer
Mutagen Category 2 - Suspected of causing genetic defects


All solutions containing formalin are suspected carcinogens, mutagens and sensitisers. The solutions should be handled with care, minimising skin contact. Safety equipment including gloves should be worn and any spill on the skin should be washed as soon as possible. Contaminated clothing should be removed immediately and washed before re-use as the chemical can soak through clothing to stay in contact with the skin for a long period of time. In general, formalin solution, like any other chemical should be treated with respect. Handle with care and avoid any situations which could potentially result in formalin spillage.

Formaldehyde vapours in the air are also harmful. The safety limit for formaldehyde in air is two part per million (2ppm). This means workers should not be exposed to formaldehyde vapour above this level (averaged over the period) for more than 15 minutes at a time. Testing machines are available to monitor the level of formaldehyde vapour in air but as a rough guide, 2ppm of formaldehyde will have a strong, unpleasant smell and will start to sting the nose and eyes on first entering the room. This check is only valid on first entering the room as the senses quickly acclimatise and will be less sensitive. In most hospitals with proper bench extraction it is unlikely that the limit will be reached in normal use but may be in the event of a spill.

Information from: Formalin Usage Guide for Hospitals - Genta, Version 2.1 (Jan 2016)  (external safety data sheet, contact laboratory if required)

Formalin may be disposed of down a sink suitable for clinical waste with copious amounts of running water in a well-ventilated room depending on local environmental rules. However, please check your local rules.


(Last reviewed 27th October 2017)