Babies come with great potential but great vulnerability. It is estimated that infants eat twice as much dust (100 mg vs. 50 mg/d), weigh one sixth as much, and are up to ten times more vulnerable than are adults to dust exposure (U.S. EPA 2002, 2003). The developing neurological, immune, digestive, and other bodily systems of infants are easily affected at low doses and these systems are less able to metabolize, detoxify, and excrete pollutants (Grandjean and Landrigan 2006; U.S. EPA 1996, 2002, 2003). Up to 11% of toddlers may exhibit pica behavior, eating nonfood items, and may consume up to 10 g of soil and dust per day (Calabrese and Stanek 1991; Mahaffey and Annest 1985). The time of life when exposure occurs may be as important as the dose (Grandjean and Landrigan 2006; Louis et al. 2007). Infants breathe more air, drink and eat more relative to their body weight, and engage in risky behaviors such as mouthing hands, toys, furniture, and other nonfood items. They crawl on floors, where they are in close proximity to carpets, and may breathe higher levels of dust (Rodes et al. 1996). Exposures early in life may trigger sensitization leading to development of chronic diseases such as asthma or predispose to cancer that takes decades to develop (Louis et al. 2007). © 2009 Springer-Verlag US.