A view of Howden Minster, an abandoned monastery in Yorkshire, UK. Howden Minster is an English Heritage field site used to study the rapid decay of magnesian limestone. Photo: Eric Doehne

The Chapter House at Howden Minster. This building dates to 1388 and has important stone carvings that should be preserved. Photo: Eric Doehne

An example of the rapid decay of magnesian limestone at Howden Minster. The loss is the result of sub-millimeter flaking of the stone. Photo: Eric Doehne

Giacomo Chiari (GCI) and Bill Martin (English Heritage) discussing the conservation of stone carvings at Howden Minster. Photo: Eric Doehne

David Carson (GCI) examining magnesium sulfate salt crusts on carved stone at Howden Minster. Photo: Eric Doehne

The time-lapse camera at the Chapter House set up by the GCI to monitor the rate and pattern of damage. English Heritage has installed an environmental monitoring system to acquire data to correlate with the damage monitoring. Photo: Eric Doehne

Eric Doehne (GCI) setting up the time-lapse camera. The Chapter House roof (top of photo) was installed in 1984. Photo: Eric Doehne

Sarah Pinchin (English Heritage) acquiring a polynomial texture map (PTM) image of the deteriorating stone surface. Photo: Eric Doehne

The four-hundred megawatt Drax Power Station, a coal-fired powerplant located a few kilometers from Howden Minster. This plant produced 563,000 tons of gypsum in 2004 as part of a SO2 reduction program. Photo: Eric Doehne

The interior of Selby Abbey, located near Drax Power Station and Howden Minster. The stone displays magnesium sulfate efflorescence. Photo: Eric Doehne

Salt crust on magnesian limestone at Selby Abbey. Photo: Eric Doehne

Salt damage to magnesian limestone columns at Selby Abbey. Photo: Eric Doehne

An abandoned abbey in York: extensive loss of magnesian limestone surfaces at St Mary's Abbey in downtown York. Photo: Eric Doehne