BIDDEFORD — Two vacationers from Massachusetts have been charged for allegedly ripping up more than 680 square feet of dune grass so they could play volleyball.

Under the state’s Natural Resources Protection Act, approved by the Legislature in 1988, it is illegal in Maine to remove sand dunes and dune grass without obtaining a permit from the state Department of Environmental Protection.

Peter J. Borowy, 28, of Auburn, Mass., and Daniel T. O’Connor, 27, of Worcester, Mass., were charged with violating the act Sunday by ripping up dune grass at Hills Beach after a neighbor complained.

If convicted, they each face fines ranging from $100 to $10,000.

Borowy said Monday he regretted ripping up the grass, but didn’t realize he was violating a state law.

“It’s always been an open spot for volleyball,” he said. “It was a couple pieces of grass there, so we took them up. But we never knew that there was any such law.

“I thought it was just grass that grew from the ocean. I thought grass was grass,” he said.

Don Witherill, of the state DEP’s land quality control bureau, said he believes public awareness has increased of the importance of preserving dune grass to prevent beach erosion.

“It’s the first time I’ve heard of (people) pulling up dune grass for volleyball,” he said.