Sanding lead paint has been noted to be one of the biggest risks of exposure to lead in the United States today. Sanding or scraping surfaces painted with lead paint creates large amounts of lead particles, which may then be inhaled. Inhaling lead particles carries a high risk to a person's health as it can affect the nervous system, blood cells and kidneys, leading to convulsions and possibly even death. Sanding lead paint will create dust containing lead particles which can also be inhaled at a later stage if allowed to settle. If children or fetuses are exposed to this lead dust over a long period of time it may lead to physical and developmental defects including lowered IQ and behavioral problems. Most homes which were built before 1960 will contain lead paint as will a significant amount built right up until the late 1970s. In these houses, lead paint may be found on walls, windowsills and outside surfaces.