Officials in New York City have issued an air quality alert telling more than 10million Americans to stay inside due to wildfire smoke.

A fire in neighboring New Jersey has burned through more than 15,000 acres since Tuesday when it erupted in Ocean County, near the shoreline.

The fire is about 54 miles south of NYC and roughly 50 percent contained. Fire crews may not be able to fully contain the blaze until rain falls this weekend.

Smoke billowing across state lines is filled with toxic chemicals and fine particles that can worsen asthma, lead to heart attacks and may increase the risk of developing cancer and dementia.

New York’s Department of Environmental Conservation and the Department of Health issued an Air Quality Health Advisory for fine particulate matter from 12am to 11:59pm Thursday.

These particles, also known as PM2.5, are tiny airborne particles with diameters that are generally 2.5 micrometers and smaller.

The advisory covers the New York City Metro area, including all five boroughs, Westchester and Rockland counties, as well as Long Island.

When inhaled, these particles burrow deep inside the lungs and can cause serious health problems.