Recently, the Environmental Working Group and Northwestern University conducted a study with which they found that 43 states are exposing its residents to a dangerous chemical via their water supply. These chemicals are referred to as PFAS and have been shown to lead to birth defects, cancer, and infertility. Chemicals of this class are used in textiles, cleaning solutions, leather, paper, and food packaging. David Andrews, a senior scientist for the Environmental Working Group, reported that these chemicals are especially dangerous because they build up in the blood, as our body cannot break them down.