BOSTON — Boston declared addiction and homelessness a public health emergency on Tuesday, a move that will help the city clear a sprawling homeless camp at the epicenter of the city’s opioid crisis.

Officials said they will get those dependent on opioids into treatment and permanent shelter after removing around 150 tents at the intersection of Massachusetts Avenue and Melnea Cass Boulevard, an area commonly known as Mass and Cass, said the city’s Chief of Health and Human Services, Marty Martinez.

The area, home to numerous methadone clinics and social services, has long been a haven for crime and illegal drug sales and use, often in the open.

The tents will not disappear overnight, acting Mayor Kim Janey said.

“Folks are looking for a magic moment where, ‘poof,’ everything is gone,” she said. “That is not how addiction works. It requires ongoing outreach to individuals. It requires work between the city, the state, and other partners to make sure that there are alternatives.”

Officials stressed that the city is not criminalizing homelessness, and no one will be forcibly removed. They said people who live in tents will be given advanced notice and offered treatment or a shelter bed.

RIZE Massachusetts, an independent nonprofit that works on addressing the opioid epidemic, lauded the city’s move to provide treatment.

“There is an urgent need for evidence-based, clinically appropriate shelter with daytime recovery supports,” the organization said in a statement. “No plan can succeed without that. A bed, without the appropriate services, is simply a bed, and that will not support people on the pathway to recovery.”

Janey’s executive order says city agencies will prioritize “enforcement of existing laws and the exercise of existing powers to prevent the placement and maintenance of these encampments in the city.”

“These existing laws, coupled with the Public Health Emergency, dictate that tents and temporary shelters will no longer be allowed on the public ways in the City of Boston,” her order says.

The tents are unfit for human habitation, said Dr. Bisola Ojikutu, executive director of the Boston Public Health Commission, because they lack “clean water, adequate hygiene facilities, and present a significant risk of weather exposure, particularly in late fall and winter.”

The residents are “at increased risk for overdose, human trafficking, sex trafficking, and other forms of victimization,” she said in the Public Health Commission’s emergency declaration.

The order also says police will continue to enforce all laws related to drug trafficking, human trafficking, disorderly conduct and trespassing. The city’s public works department will also clean the area and improve road and sidewalk safety.