Since it opened in the late 1980s, the Tullytown landfill has drawn the ire of its neighbors.

The landfill, located in Tullytown, Pa., is owned by Waste Management and sits on the bank of Delaware River. On the other side of the river are the residential neighborhoods of Florence, N.J. For years, the residents have alleged noxious odors have emanated from the Tullytown landfill.

A local group called Citizens Against the Smell of Tullytown claims to have been making calls to WM’s odor hotline for years to no avail, then recently finding out that those odor complaints were allegedly never reported to any outside agency.

Once it was known that odor complaints should be made directly to the local environmental agencies, “numerous” complaints were received by the Pennsylvania Department of Environmental Protection (DEP) alleging noxious odors at the landfill, says Amanda Witman of DEP.

DEP began its own investigation, and issued a notice of violation in October 2014, citing WM for nuisance odors emanating from the landfill.

In response to the violation notice, WM has made a number of improvements, including a 20 percent reduction in total waste at the landfill, a 66 percent reduction in sewage sludge waste, using additional soil to prevent fresh waste from creating odors, installing 21 new landfill gas wells, news synthetic capping, plus new misting lines. The odor-related improvements have already reportedly cost WM millions.

Despite those improvements, a lawsuit was filed in December in the U.S. District for the Eastern District of Pennsylvania by New Jersey-based law firm Kamensky Cohen & Riechelson on behalf of a handful of residents around the landfill. The firm also recently sent out notices seeking additional plaintiffs to add to the case. The hope, according to the firm, is to apply for class-action status, and that the case will result in an injunction against WM that will require the company to clean up the landfill and prevent odors from crossing over to residential neighborhoods.

Although there has been little progress on the lawsuit, WM is moving ahead with improvements at the site as it works toward renewing its operations permit that is set to expire May 23, 2015.

DEP conducted a public hearing March 25 related to WM’s permit renewal application, and DEP says any comments collected at that hearing will be considered as the renewal application is evaluated. Written comments will also be accepted by DEP through April 10.