Skip to content
Go behind the scenes with Collections Conservator Jess Routleff-Jones as she explains the tricky business of tidying up a mercury spill.

At the Blythe House object store in west London, over 50 colleagues are working hard to study, record, digitise, pack and transport over 300,000 incredible items from the Science Museum Group Collection to their new home at the National Collections Centre in Wiltshire, which will open regularly to the public from 2023.

This blog series goes behind the scenes with the teams making this ambitious project happen.


Since you last heard from us we have welcomed two new Conservators to the team, Laura and myself, Jess. We’ve been busy studying the condition of over 1800 objects from the collection and have conserved 86 objects as part of the project.

Our job is to care for the objects in the collection, conserving them where needed and preparing items for display, photography and travel.

One day we might be reconstructing a ceramic vase, removing corrosion from a metal surface or stabilising an acidic leather surface.

A large part of our role is to remediate the hazardous substances used in historic objects. Some machines in the collection contain various potentially hazardous oils and some items in both the Time Measurement and Meteorology collections contain mercury.

Tackling hazardous lead corrosion, potentially toxic medicines and mercury or dealing with polychlorinated biphenyl (PCB) is something we are all well trained in.

Objects can leak for various reasons. As they age, certain parts of materials can begin to sag and lose strength sometimes due to the weight of the liquid within the item. Although leak can sound alarming, usually the hazardous substances will already be contained within packaging or containers.

There is no immediate risk to people, or surrounding objects if the object remains in our stores, but for objects to be safely packed and moved to the National Collections Centre, these leaks need to be resolved.

Conservators are trained to deal with hazardous substances and handle objects, and it is our responsibility to ensure that the objects are safe to be moved by other teams. We also count objects which are chemically degrading and “weeping” to be leaking, such as old plastics.

Recently, Ruth, Laura and I assembled to deal with a small mercury leak coming from a barometer in one of our storerooms.

Ruth, Laura and Jess in their Personal Protective Equipment

The spill was not active and was being safely managed, contained within polythene sheeting in a sturdy tub.  However the source of the leak needed to be investigated so that during transport we could be confident that no further leaks would occur.

Despite its toxicity, mercury is a mesmerising material. It is extremely heavy, dense and is molten at room temperature.

This allows it to flow through small crevices easily and therefore all surfaces must be protected. Mercury evaporates very slowly and gradually turns to toxic mercury vapor which is colourless and odourless. Therefore opening an enclosure that has contained mercury can be extremely hazardous to health.

With this in mind, we donned our PPE (Personal Protective Equipment), gloves, goggles, aprons and face-fitted vapour filtering masks.

As soon as we became aware of the leak we stopped access to the storeroom. We also ventilated the area and placed fans near the object to circulate the vapour.

Between us we managed to collect the mercury using pipettes and large syringes – a challenging task due to the weight of the substance.

We transferred the mercury into a sealable tub for hazardous waste disposal. As the mercury spill has been remediated, the barometer is now safe to be moved to the National Collections Centre.

As a precaution, however, we will continue to monitor the mercury vapour levels and check for further leaks from the barometer until its voyage out of Blythe House.