Parts of eastern and Midcoast Maine are under an air quality alert following a fire at an Orrington trash plant that is releasing high particle pollution levels.

The Maine Department of Environmental Protection issued the alert Thursday, saying that the pollution levels are expected to reach the “unhealthy for sensitive groups” level on Thursday and Friday.

The smoke is from a fire that started Tuesday night in Orrington at the Penobscot Energy Recovery Company building that contains a 40-foot-high pile of trash, according to the local fire department.

The fire is expected to burn for at least one more day and winds in the Penobscot River Valley are likely to come from the south for another 24 hours, according to DEP.

Elevated pollution can affect children, the elderly and those with heart and lung disease such as asthma, bronchitis or COPD. Symptoms include coughing, shortness of breath, throat irritation and mild chest pain, DEP said in a release.

The agency is advising people to avoid strenuous outdoor activity, close windows and for those with asthma to keep quick-relief medications close by.