Among the most prominent recent additions to the Cambridge skyline are the big green chimneys on the top of the Department of Chemistry. They contain flues from the fume cupboards, which are diluted with lots of fresh air and evacuated at high level.

The building was constructed in the 1950s, and originally had mahogany fume hoods built into the window frames. A major re-servicing has been going on in several phases for the last nine or ten years.

The green colour is copper: this is naturally a bright orange, which turns dark brown and then gradually becomes green. The new metal has been pre-patinated so that it matches the colour of the copper roofs of the original building. The big ducts carrying the flues up the south side of the building are clad in fritted glass – clear glass that has had a pattern etched on to it, so that the ducts inside can just be glimpsed but are not too obvious. The ducts, and a series of metal louvers, also act as sun protection to the south-facing windows, which previously used to get overheated in the summer.