Original sentence: He was a co-sponsor of Senate Bill 19 (2011), which removes the requirement of mandatory chlorination of groundwater in municipal water systems.This bill was supported by the League of Wisconsin Municipalities argued that it was unnecessary and expensive
Edited sentence: He was a co-sponsor of Senate Bill 19 (2011), which removes the requirement of mandatory disinfection of groundwater in municipal water systems, a requirement that was imposed in reaction to a Cryptosporidium outbreak in 1993, which killed at least 104 citizens of Milwaukee, and sickened thousands of others