The article desribes the problems which arose when an uncompleted storage building was left without controlled conditions during a hot humid summer in Detroit. Mildew growth was not initially considered a serious problem unitl it began to develop. It was difficult to find anyone with knowledge of what to do, what products to use, that would be safe for both those applying the fungicide and for the materials subsequently to be stored in the location (primarily metals). The mould growing was then identified, found to be dangerous to man, and treated with copper naphthenate. The storage building belonged to the municipality an further problems were caused by failure to appreciate the need to incorporate into contracts responsibility for the different stages of the curative treatment given.