DAISETTA, Texas (AP) — When the massive sinkhole first appeared in Daisetta in May 2008, some residents had feared it might engulf their small Southeast Texas town.

But after growing close to 600 feet (183 m) across and 75 feet (23 m) deep, it stabilized, swallowing up some oil tanks and several vehicles but sparing nearby homes. Some residents used humor to calm their fears, making “Sinkhole de Mayo” T-shirts, a reference to Cinco de Mayo. For others, the sinkhole, which eventually filled with water, became a new fishing spot.

“It was just a pond after that, just a story that we told our kids. We just learned how to live with it,” Krystal Parrish, one of the approximately 1,000 residents who live in the town located about 60 miles (97 km) northeast of Houston, said Tuesday.

But earlier this month, city officials announced the sinkhole had expanded after a long hibernation, renewing fears from some residents. Officials say there hasn’t been any significant expansion since the new growth was detected April 2, but they’re monitoring the sinkhole and keeping the public informed. In a preliminary report released Thursday, state researchers said the expansion was actually a new and smaller sinkhole that formed adjacent to the one from 2008.

“I don’t think (residents) should panic or anything. But it’s something that they should watch,” said Richard Howe, a private geologist with Houston-based Terra Cognita who’s helping Daisetta officials monitor the sinkhole.

But Parrish and some other residents say the city hasn’t sufficiently updated the public.

“I’m not gonna lie, I’m pretty creeped out by it because it’s twice in my lifetime and my house is like a quarter mile from the sinkhole,” said Parrish as she watched her son during a high school baseball game.

Daisetta sits on a salt dome, a natural formation created below the ground over millions of years where oil brine and natural gas accumulate.

Salt domes create good conditions where oil can migrate and accumulate, Howe said. This was the reason Daisetta became a booming oil town in the early 1900s. The sustained oil drilling along the salt dome over decades could have contributed to creating the sinkhole, Howe said. Investigators had also considered saltwater waste that was being stored underground by an oil and gas waste well business next to the sinkhole as a possible cause.

But Howe said a cause for the 2008 sinkhole was never determined. A more comprehensive study could be done, but it would be costly and “a small town like this is not flush with cash,” he said. Howe, who also helped Daisetta in 2008, is working for the city on a volunteer basis.

Howe suggested the underground cavern in the salt dome that first collapsed and formed the 2008 sinkhole likely expanded, creating a new sinkhole that seems to have merged with the original one.

In the preliminary report, the Bureau of Economic Geology, a research unit at the University of Texas, said the new sinkhole has a diameter of about 230 feet (70 m) and is about 30 feet (9 m) deep. The report said there was no indication the new sinkhole had impacted Farm-to-Market Road 770, the main roadway through the town.

The new sinkhole may or may not expand much, but more study is recommended “to better understand the cause … to minimize risk associated with similar possible future events,” according to the report by the bureau, which functions as the State Geological Survey.

Sinkholes tend to be common in regions where soluble rocks, including salt domes and limestone, can be dissolved by groundwater, according to the U.S. Geological Survey. Florida, for example, sits above limestone and is highly susceptible to sinkholes.

Howe said officials have placed steel posts 50 feet (15 m) apart in a pasture area near the sinkhole to monitor any changes in their elevation and to act “as an early warning if this thing continues to move south toward homes and buildings.”

“This thing could be like this for another 15 years … or it could be 100 years, or it could change tomorrow. It’s just no way to predict it,” said Howe, adding nothing can be done to stop the sinkhole if it continues expanding.

The expanding sinkhole is located near the high school campus, as well as various homes and a new Family Dollar/Dollar Tree store that opened just days after the new growth was discovered.

At the site of the shuttered oil and gas waste well business that’s been taken over by the expanding sinkhole, a road that connected one end of the location to the other has been washed away. Several large tanks, which officials say are empty, were in the water. A portion of a metal warehouse was being consumed by the sinkhole, while large cracks could be seen on the ground around the building.

Officials with the U.S. Environmental Protection Agency and the Texas Commission on Environmental Quality, or TCEQ, had relocated six large tanks with an unknown substance from the cracked earth and asphalt near the sinkhole so they could be tested, the TCEQ said in an email Wednesday.

“Due to the imminent threats to human health and the environment, TCEQ and U.S. EPA proceeded quickly to mitigate the potential for chemical releases,” TCEQ said.

Daisetta resident Alexis Laird, 25, a mother of three kids, said she hadn’t really thought much about the sinkhole since first seeing it as a fourth-grader in 2008. Now she’s worried about it, as her apartment is located less than two blocks away from it. She said she wants officials to be more proactive in their updates to residents.

“It doesn’t matter whether it’s good or bad or a minuscule amount of information. … Tell the people that live here,” she said.

Daisetta City Secretary Joan Caruthers said officials are working to set up a website that will provide updates and are planning to hold a public meeting in the future. Caruthers said they want “a little more information” before scheduling the public meeting.

After the sinkhole appeared in 2008, county commissioners asked the state to set up monitoring devices that could be an early warning system.

Caruthers said she’s not aware if any such monitoring system from the state was ever set up. The sinkhole was monitored for several years after 2008, but there was no recent active monitoring by the city, she said.

Christine Bautsch, Laird’s mother, described Daisetta as a friendly town where “everybody pretty much knows everybody” and residents come together in a time of crisis, including a growing sinkhole.

“There is really good people here and they take care of each other. … We’ll pull together,” Bautsch said. ___ Follow Juan A. Lozano on Twitter at https://twitter.com/juanlozano70.