State and federal officials are collecting air and water samples near the site of a trash plant fire in Orrington that’s been burning since Tuesday night.

So far, air quality studies have not shown concerning levels of chemicals, but monitoring continues, according to an update from the Maine Department of Environmental Protection issued Thursday evening.

Samples are coming from the entrance of the Eagle Point Energy Center, where the fire occurred in a 40-foot-high pile of trash; Lots of Love Daycare and the Edythe Dyer Community Library. In addition, staff “could smell but not see smoke” at the George B. Weatherbee School in Hampden and the Center Drive School.

In addition, water samples are being collected from the Penobscot River, which is west of the fire site.

On Thursday, state officials issued an air quality alert for eastern and Mid-Coast Maine because of concerns about high particle pollution levels.

They warned that the levels could reach the threshold of “unhealthy for sensitive groups” through Friday.

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.

The Maine Center for Disease Control and Prevention is monitoring area emergency room visits to see whether people are requiring emergency care because of the fire. At this point, there has been no increase in visits related to the fire, according to DEP.