The investigation into how chunks of lead washed up along Keyport’s shore is set to begin Monday.

About 200 yards of the shoreline will be closed while Department of Environmental Protection agents collect and analyze more of the oddly-shaped structures, known as slag, that have tested positive for lead.

“We don't see this as an urgent risk to public health,” said NJDEP Commissioner Shawn LaTourrette. “No need for a beach closure.”

Officials added that - as of now - the level of lead found isn’t enough to issue a sweeping order not to swim or eat fish from the water.

“Notwithstanding the level, lead has no place being deposited upon our shores,” LaTourrette said. “If we find that someone has broken the environmental laws and risks the good health of our people or communities, we will hold them responsible.”

Testing more of the pieces will help identify their source. The DEP said Friday that they don’t believe it came from the Raritan Bay Superfund Site - a seawall just miles away made of this slag.

The pieces don’t look out of place until one takes a closer look.

“They look like rocks, but it has no moss, no seaweed, nothing on it,” said resident Karen Dittmer.

Neighbors said they’ve seen the slag for years. More recently, they’ve noticed a startling increase in the number of dead crabs that have washed ashore.

They said a “do not consume fish or crabs” sign that once stood at the beach was removed years ago.

“I love this beach,” Dittmer said. “My husband fishes down here, my son fishes down here. But now when I come down, I make sure I have boots on because I don’t want anything getting inside my skin."