– The first sign something had gone wrong at Mosaic’s phosphate plant happened on Saturday, Aug. 27. Workers checked the water level in a 78-acre pond of polluted water sitting atop a 190-foot phosphogypsum stack and discovered it had dropped more than a foot.

They believed it was just the wind blowing the water around. But about 11 a.m. Sunday, they realized the level had dropped 3 feet.

How could a pool of acidic water on top of a massive gypsum stack suddenly start draining away? A sinkhole 45 feet wide and 220 feet deep had opened up. Down went 215 million gallons of contaminated water, gurgling into the aquifer that supplies the region’s drinking water.

Geologists say the reason for the drop should have been obvious. But state records show that it took Mosaic officials more than a week to use the word “sinkhole.”

As contaminated water poured into the aquifer, Mosaic Co., based in Plymouth, Minn., and state officials both avoided using the “s-word” until Sept. 9. The public didn’t find out until Sept. 15 — 19 days after the crisis started.

Even the state’s top environmental regulator said he didn’t know it was a sinkhole. That’s why he didn’t tell Gov. Rick Scott about it until Sept. 16, the day after it hit the news.

“I knew at the time in late August that there was a water loss incident,” Florida Department of Environmental Protection (DEP) Secretary Jon Steverson told reporters last week. “I was not aware of the sinkhole until a much later point in time.”

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On Aug. 28, seven hours after spotting the water loss, Mosaic officials called the DEP. They did not use the word “sinkhole.”

“Caller is reporting a release of phosphoric acid process water from a fertilizer manufacturing facility,” the DEP noted. “The amount released and the cause are unknown and under investigation.”

Phosphoric acid process water, stored in a pond atop the gyp stack, is a byproduct of turning phosphate into fertilizer. It is a pollutant, but records show that at no point did anyone suggest telling the plant’s neighbors. State law didn’t require that — a law the governor later called “stupid” and vowed to change.

Two hours later, company officials e-mailed a report to DEP. There was no mention of a sinkhole. Instead it focused on an apparent tear in the gyp stack’s bottom polyethylene liner, which was supposed to keep pollution from seeping into the aquifer.

“During routine inspections on August 28, 2016, Mosaic observed and confirmed a steady decline of water level in the West Cell of the South Gypsum Stack,” the Mosaic report said.

Mosaic officials estimated that 35 million gallons a day was pouring out of the pond. But they later said there was “no visual feature/indication noted” that would tell them why.

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Should the world’s largest phosphate company have known right away it was a sinkhole?

Robert Brinkmann, who literally wrote the book on Florida sinkholes, said yes.

“If they knew there was a tear in the liner, they knew there was something draining that water down into the aquifer,” said Brinkmann, a Hofstra University geology professor who wrote Florida Sinkholes: Science and Policy.

The answer also seemed obvious to George Veni, executive director of the National Cave and Karst Research Institute in New Mexico.

“It’s a sinkhole!” Veni said. “By definition it’s a natural depression in the surface and water that gets poured into it goes down to the bottom. It’s a big hole in the ground.”

Longtime Palm Harbor sinkhole expert N.S. “Sandy” Nettles laughed when he heard about Mosaic’s reluctance to use the “s-word.”

“That’s just ridiculous,” said Nettles, who used to work in the phosphate industry. “I don’t know who came up with the idea that if you don’t call it a sinkhole, it’s not a sinkhole. Things are still going down into the aquifer.” A torn liner, he added, “means it was probably leaking for a very long time.”

Another reason Mosaic should have known it was a sinkhole, they said, was history.

One of Florida’s most notorious sinkholes opened in 1994 at the same Mulberry phosphate facility where the Aug. 28 sinkhole opened. That sinkhole — 160 feet wide and plunging 200 feet — also sucked the pond from a gyp stack into the aquifer. It opened 1¼ miles from the new sinkhole.

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State inspectors arrived at the plant within 24 hours of Mosaic’s call. In an Aug. 29 report, they said they told Mosaic to build a well to pump the pollution out. It didn’t start pumping until Sept. 10.

The word “sinkhole” did not appear in that DEP report. It was a “water loss incident.”

Mosaic workers began trying to pump water from the pond to another spot, but their pumps couldn’t keep up with how fast it was pouring into the aquifer.

A Sept. 3 report to Mosaic and DEP by Mosaic consultant Ardaman & Associates also avoided using “sinkhole,” instead saying the pond’s disappearance “may have been caused by an anomaly likely connected to the Floridan aquifer system.”

By Sept. 6, the pond completely disappeared. Mosaic officials said they’d spotted “a fissure.”

“Mosaic generally began referring to this as a sinkhole on Sept. 6 when we could see the hole,” said Mosaic spokeswoman Jackie Barron. Yet a Sept. 7 Mosaic letter still called it the “water loss incident.”

Mosaic finally used the word “sinkhole” in a Sept. 9 letter to the DEP and the federal Environmental Protection Agency. The EPA needed to know because last year it fined Mosaic nearly $2 billion over mishandling hazardous waste at eight company sites — one of them Mulberry.

On Sept. 15, a WFLA-TV reporter called Mosaic and the DEP to ask about rumors regarding the sinkhole. Only then did Mosaic make it public. It has since apologized for keeping quiet.

Last week, Steverson told the Cabinet about a consent order his agency had worked out to guarantee Mosaic would clean up the pollution and fill the sinkhole. He said he had seen no signs of negligence, but if that changed, “we’re going to protect the citizens and the resources of this state.”