Chris Davis tar
© Florida TodayChris Davis was on Melbourne Beach when he spotted a glob of tar
Officials await tests this week to determine whether a pancake-sized tar mat, picked up on Melbourne Beach, came from the BP oil spill or is just usual gunk that occasionally washes up.

Cindy Leckey, a supervisor for Brevard Environmental Health Services, called it "highly unlikely" the tar is from the spill.

But she and other officials warned beachgoers to leave any tar-like substance they see to those trained to handle it.

"Nobody should be touching anything," Leckey told Local 6 News partner Florida Today. Dial 211 to report it instead, she said.

Officials said it's too early to see tar on Brevard's beaches from the Gulf of Mexico spill, but they'll train volunteers Wednesday night on how to identify and report problems that might develop.

Chris Davis, visiting from Tennessee, said he found the tar mat Friday while walking the beach.

"I looked around, and I didn't find any more," he said. "It smells like asphalt."

Coast Guard officials cut out a 1-inch square segment of the tar for testing, Davis said. The rest he keeps in a jar as a souvenir.

On June 22, a woman and her neighbor found two tar balls on Satellite Beach. However, tests by the Coast Guard's Marine Safety Laboratory in New London, Conn., found the tar was processed mechanical oil from a boat's bilge.

Clumps can form naturally from oil seeping from the ocean floor or from oily bilges and ballast tanks of passing ships.

Larger tar chunks can result from oil that clumps together after a spill or upwelling. But local tar balls are typically small and lurk beneath the sand until someone steps on them.

They cling to feet, smell up the beach as they evaporate and generally settle out among the washed-up seaweed at the dune line. Eventually, they dry up, turn brown and crumble.

Stricter shipping regulations have reduced the tar along Brevard's beaches from what used to wash in 20 years ago.

Coast Guard officials can determine oil origins from unique chemical fingerprints. Oil is a complex mix of thousands of organic compounds, chemically converted under varying geological conditions.