The World Health Organization has recommended that noise during sleep be limited to a level of 35 decibels, and governments are beginning to place restrictions on noise levels in both residential and business environments. In the Netherlands, for example, regulations specify that new homes may not be built in areas of high noise levels— those that exceed average noise levels of 50 decibels. In the United States, employers must provide hearing protection for those who endure noise levels of 90 decibels for more than eight hours a day.