ORLANDO — Florida’s shoreline was apparently untouched by any raw petroleum before the Deepwater Horizon disaster smothered the western Panhandle with crude oil in June.
That’s according to what authorities consider to be the most exhaustive detective work yet on tar balls found along the state’s 1,260 miles of coast.
U.S. Coast Guard lab findings defy the long-standing belief that a regular ingredient of at least some of the tar balls that for years have turned up occasionally on state beaches is either crude spilled during offshore drilling or oil that seeped from natural vents under the Gulf.
Of the 192 batches of Florida tar-ball samples sent since mid-May to a Coast Guard laboratory in Connecticut, the vast majority have turned out to be lumps of heavy fuel oil, dark and syrupy as molasses and commonly used to power oceangoing ships.
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None of the samples was identified as containing unprocessed, crude oil; a few samples proved to be nothing more than hardened mud; and nearly 20 samples had been severely altered by sunlight, oxygen and bacteria and were thought to be many months or years old, said Wayne Gronlund, manager of the Coast Guard Marine Safety Laboratory in Connecticut.
Those aging tar balls “were so heavily weathered, we couldn’t make a declaration about whether they were crude or heavy fuel,” said Gronlund, who described them as similar to chunks of asphalt.
Gronlund said his chemists, when examining fresher samples, can easily distinguish between the chemical fingerprint of crude oil and those of refined petroleum products such as heavy fuel oil, diesel and various lubricants.
The search for tar balls along Florida shores took on heightened urgency two months ago when dozens of blobs of oily tar began to wash up in Big Pine Key, Key West and the Dry Tortugas.
Authorities then thought it unlikely that crude oil could have drifted so quickly across 500 miles of open Gulf from the BP PLC oil-well blowout, which began April 20 with an explosion and fire on the drilling rig Deepwater Horizon nearly 50 miles south of Louisiana.
A day after those tar balls first appeared in the Keys, a Coast Guard jet carried what was deemed to be “samples of national significance” to the service’s laboratory, which determined within hours that they were composed of heavy fuel oil.
The source was never identified.
Still, the Keys event triggered a statewide surge of concern about the potential for crude oil to ride currents to any spot along Florida’s coast.
“People’s awareness for tar balls has been heightened because of the spill so they went out looking for tar balls and lo and behold they found tar balls,” said David Palandro, a scientist with the Florida Fish and Wildlife Conservation Commission.
Advocates of drilling for oil in waters near the Florida coast have argued that the state has already learned to tolerate the occasional landfall of crude in the form of tar balls created not by drilling or tanker-ship accidents but by seepage from natural vents that connect petroleum reservoirs deep underground to the seafloor.
“Natural seepage accounts for virtually all perceived ‘oil spills’ in the Gulf,” stated a glossy brochure with the subtitle, “It’s time for facts, not fear,” that was widely distributed in Florida last year by drilling supporters lobbying the public and the Legislature.
“They try to draw the conclusion that any oil found on the beaches is actually from these natural causes,” said Eric Draper, executive director of Audubon of Florida. “Their argument is if most of the oil comes from seeps, then most of the oil on beaches must come from seeps.”
David Mica, executive director of the pro-drilling Florida Petroleum Council, said he doesn’t “recall ever asserting that they (tar balls) were all naturally occurring.”
The vast majority of tar balls collected and tested during the past two months were found in the Keys and Southeast Florida, where the shipping lanes, including some of the nation’s busiest, pass within miles of the coast.
Experts say the tightening of environmental laws and enforcement efforts have reduced the amount of such oil discharged from ships in recent years.
The ruptured BP well, under nearly a mile of seawater, continues to spew as much as 35,000 barrels — or nearly 150 million gallons — of crude into the Gulf each day.