On Brønnøya we can today see remains of lime kilns and extraction of lime. Three lime kilns have been registered on the island, in addition to the fact that the area bears the mark of lime mill operations. The largest lime kiln can be seen in Sandbukta, where it rises majestically only five meters from the Oslo Fjord.

The lime kiln at Sandbukta was built in 1874. It is square, built of stone and built with lime. The oven is in good condition, although the individual places are slightly cracked. The lime kiln is only five meters from the sea. Today, both the kiln construction and the associated ramp on the slope behind are protected.