In a laboratory Thorium Nitrate was used in the past for the analysis of a product. This laboratory did have a permit to work with this radioactive substance but it was revoked due to better ways to do the analysis without the use of open radioactive sources. Several years ago they thought all open radioactive sources were removed. In 2009 a remainder of this substance was found in the laboratory. We investigated the thorium nitrate and concluded a permit was required. Handling radioactive materials without a permit is a serious violation of the Act on Nuclear Energy. We have contacted the authorities directly and explained the situation. All parties agreed that this source had to be disposed off as soon as possible. Through the vigilance of laboratory staff and the careful and competent actions of our level 3 experts the employees and the environment were not contaminated.