The governor of Washington state declared a state of emergency Friday over a measles outbreak that has sickened dozens of people in a county with one of the state's lowest vaccination rates.

Gov. Jay Inslee said in a statement that the outbreak in Clark County "creates an extreme public health risk" that could spread throughout the state. Under Inslee's declaration, state agencies can use all available resources to help affected areas and additional medical resources can be requested from other states.

Clark County Public Health has confirmed 30 measles cases since January 1 and identified another nine suspected cases. Twenty-six of the confirmed cases were people who were not immunized for measles, the agency said. Most of the confirmed cases — 21 — were with children between 1 and 10 years old. Eight cases involved people 11 to 18 years old, and one case was someone 19 to 29.

The county released a list of public places where infected children visited, which included several schools and churches, the Portland, Oregon airport and a Costco.

This story was originally published by CBS.