WINDHAM — The owner of the Keddy Mill is asking for more time to assess the extent of contamination at its site in south Windham.

The Maine Department of Environmental Protection had asked mill owner HRC Village at Little Falls to submit a plan by Friday for testing the site for contaminants.

The owner responded with a letter asking to extend that deadline until Dec. 16, said David Wright, director of the DEP’s remediation division.

Previous testing found the widespread presence of toxic polychlorinated biphenyls, known as PCBs, in the concrete of the mill building and in the ground throughout the property.

Wright said a more comprehensive assessment of the level of contamination is necessary to determine the best way to clean up the site. That cleanup, he said, may be led by the owner, the DEP or the U.S. Environmental Protection Agency.

DEP officials today were still considering whether to grant an extension to the mill owner, or move forward with a different plan.

HRC Village at Little Falls had planned to develop a condominium complex in the building, the former home of a paper mill and later a foundry, which closed 40 years ago. That plan, however, was shelved in 2009, amidst the country’s recession and mounting environmental concerns at the site.