You can not see, taste or smell this toxic: lead. The long-term effects of childhood lead exposure can be very severe. Children can suffer impaired intellectual development, stunted growth, hearing and behavior problems. A study published in the July 2005 issue of Environmental Health Perspectives found there is no safe threshold for adverse consequences of children's exposure to lead. The Center for Disease Control has set a standard of no more than 10 micrograms per deciliter of blood for children under the age of 5. However, the aforementioned study found that impairments from lower levels of lead are proportionally greater than impairments from higher levels. The complete study is available at http://www.ehponline.org/.
Lead was used in many homes and residential housing units on college campuses built before 1960. If the building you are in was built after 1980, it likely does not contain lead-based interior paint but there may be lead-based paint on its exterior surfaces. Lead-based paint is dangerous if small pieces peel or chip off and are eaten. When surfaces that have lead paint such as old window sills or doors are rubbed together they create dust. This lead-filled dust can be a threat to children's developing respiratory system.
Old or imported plastic mini-blinds have been found to have lead content, so throw them away. Also, plastic toys made from rigid PVC plastic can contain lead. Be sure to be on the lookout for inexpensive jewelry in your dramatic play areas, because such items may have a lead content.