DENVER (CBS4) – State lawmakers are once again debating a bill that would make it harder for parents to opt-out of vaccinating their children. The controversial measure is up for a second reading in the state House on Monday.

(CNN)

The bill requires the state health department to develop a standardized form and a strict process for parents who choose to not immunize their children — whether it be for medical, personal or religious reasons.

(Photo by Chris Hondros/Getty Images)

Additionally, the bill will overhaul how the state keeps track of who has received immunizations.

Related: Doctors Encourage Coloradans To Get Measles Vaccinations

The bill’s sponsors say they want schools to be safe for all kids.

Colorado ranks among the lowest when it comes to vaccination rates, including diseases like measles, mumps, chicken pox and whooping cough.