The crisis that began unfolding in Flint, Mich., in 2014 provided a tragic reminder of the dangers of lead exposure. The drinking water of an entire city had been contaminated with lead. More than 8,000 children under the age of six drank lead-contaminated water.

A potent neurotoxin, lead affects how our children learn, grow and behave. According to the EPA,"In children, low levels of [lead] exposure have been linked to damage to the central and peripheral nervous systems, learning disabilities, shorter stature, impaired hearing, and impaired formation and function of blood cells." Lead is so toxic that the American Academy of Pediatrics recommends a health standard of 1 part per billion.

Now we know this toxic threat extends well beyond Flint.

TexPIRG Education Fund research has found that lead exposure is a national problem, and Texas isn't immune. A total of 60 schools in Fort Worth, and a dozen so far in Dallas, have found lead in water above 15 parts per billion (ppb), the level at which the EPA recommends actions are taken to reduce lead levels.

In all likelihood, these confirmed cases are just the tip of the iceberg. Most schools have at least some lead in their pipes, plumbing, faucets, or drinking fountains. And where there is lead, there is risk of contamination.