After the discovery of the tomb, scientists found deterioration in many paintings caused by water damage, bacterial growth, salt formation, and recently, the humidity of visitors' breath. In 1986, an operation to restore all the paintings within the tomb and to replace over 3,000 years worth of dust and soot with paper pasted to the fragile walls and ceilings to preserve the paintings was embarked upon by the Egyptian Antiquities Organisation and the Getty Conservation Institute; the actual restoration work began in 1988 and was completed in April 1992. Upon completion of the restoration work, Egyptian authorities decided to severely restrict public access to the tomb in order to preserve the delicate paintings found within. Five years later, Egypt's Prime Minister, Hisham Zazao, declared the tomb to be reopened to visitors, 150 visitors at a time. In 2006, the tomb was restricted to visitors once again, except for private tours of a maximum of 20 people purchasing a license for US$3000.