Chemical fires and releases across Houston in the last year, and the Houston Chronicle's Chemical Breakdown series, have shed light on problems with toxic stockpiles and emergency response. The bill would create a statewide "opt-out" system, meaning phone users would get the alerts unless they deliberately choose not to, just as some Amber Alerts and weather warnings are pushed to mobile phones automatically. Initial reports linked the smell to a chemical refinery, but officials later walked back that assessment, and the incident remains under investigation. [...] there was no air monitoring, and the U.S.