Safe Disposal of Gypsum Plaster & Old Models


Gypsum (calcium sulphate) is generally inert but given the right circumstances it can be highly absorbent.

Gypsum will generate hydrogen sulphide gas from microbial action when mixed with biodegradable waste, if it enters a normal mixed landfill.

Water brings about hardening, damage and eventually deterioration, releasing the hydrogen sulphide into the atmosphere.

This gas is highly toxic, malodorous and has serious ramifications for public health and safety, so appropriate disposal methods should be followed. Despite an existing EU Directive on this matter the legislation in Ireland does not specifically deal with Gypsum by-products in healthcare setting.


  1. If you have large quantities of old models or you produce large qualities of waste Gypsum then ask your authorised healthcare waste company to supply you with an appropriate Gypsum Collection Bin. These bins come in a variety of sizes.
  2. If you have infrequent, small quantities of Gypsum waste simply include it in your clinical waste bags. These bags go for incineration.
  3. Never allow Gypsum or Plaster to be placed in domestic/general waste as routinely this goes to landfill.

Local Authority Waste enforcement officers will be visiting dental practices in 2020. They will initially be looking at Amalgam Separators (S.I. No. 533 of 2018). As an element of their inspection they may also inspect all other forms of waste, hazardous, general and recycling.

It’s a good time now to review your Waste Management Policy ensuring that if it applies to you that Gypsum disposal is included in your policy document.