California's legislature sent a bill Monday to Gov. Jerry Brown that would place tougher immunization requirements on parents with children in schools, bringing to an end voluntary exemptions from medical vaccines based on personal or religious beliefs in the state, the L.A. Times reports.

Under current California state immunization laws, parents may choose whether or not to immunize their children to diseases such as measles and whooping cough if religious or personal beliefs about the procedure's safety get in the way. If passed, the measure would make California's some of the toughest vaccination laws in the country.

The bill was introduced to combat what lawmakers see as a public health danger spurred by ill-informed parents. Those fears were embodied in a months-long measles outbreak at Disneyland in California that saw the disease spread to more than 150 people. No deaths were reported as a result of the outbreak, but the particular strain of measles was the same one that wreaked havoc in the Philippines last year, infecting more than 50,000 people and killing 110.

The California bill would make it more difficult for parents to chose not to have their children immunized from diseases such as measles. Exemptions would still be possible with doctor-approved medical conditions like allergies or immune deficiencies, which could be exacerbated by vaccines. Children attending homeschool-type programs can also be exempted.

Though the bill, authored by Sen. and pediatrician Richard Pan (D-Sacramento), received bipartisan support in the legislature, it has needled the contentious health-and-safety debate simmering at the core of the vaccination issue between parents, public health officials, and a fervid group of so-called "anti-vaxxers," mostly parents who ardently oppose immunizing their children, saying the practice is unnecessary and dangerous, and infringes on their privacy rights. According to the Times, Pan has received death threats over the bill, and has been the subject––along with Sen. Bill Monning (D-Carmel), a vocal supporter––of filings asking for his removal from office.

California has more than 13,500 kindergartners whose parents have waived vaccinations based on personal beliefs, the paper notes.

The legislature approved the vote early Monday afternoon and now the bill heads to Gov. Jerry Brown's desk, where it is is to be "closely considered," a spokesman told the Times. If adopted, California would become the 32nd state to place bans on foregoing vaccinations because of personal beliefs, but just the third to do so on the basis of religious beliefs, joining West Virginia and Mississippi.