Seventeen years after a group of schoolchildren discovered hundreds of deformed frogs that launched a nationwide scientific mystery, the biologist who led the search for answers was back at Ney Pond.

Eyes spearing the grass and net poised, Judy Helgen of Roseville wanted to see for herself how the frogs were faring.

At first, nothing stirred under the late-summer sun but insects. Then something moved, and her net quickly snared the first leopard frog of the day.

"Ah, good. This guy looks OK," she said. But then 10-year-old Greg Pollack, son of two early frog students, netted a second frog. This one had problems.

It was a similar day in 1995 when 10 seventh- and eighth-graders from a nearby experimental charter school made their startling discovery at Ney Nature Center, 55 miles southwest of the Twin Cities. Soon there were reports from other parts of Minnesota, then other states.

Some had missing or extra legs, misplaced eyes, misshapen jaws, spinal defects, intestinal blockages and other deformities. Most were young.

A research biologist at the Minnesota Pollution Control Agency (MPCA), Helgen, now retired, talked to the teacher and was on the scene within days, interviewing students and landowners and running experiments to find out what was causing deformities in unprecedented numbers.

"Was this just some anomaly, or were the frogs warning us that their environment, and ours, was in real peril?" Helgen recalls thinking. "The struggle to find answers changed all of us, researchers and students."

For five years, Helgen and the students were in the thick of the investigation. That search led her to write "Peril in the Ponds," a new book that chronicles her search for answers, and butting heads with her bosses over how far to go.

"It was an exhilarating time, but also very frustrating," she said. "Was it pesticides, or maybe parasites or predators like dragonfly nymphs? Was climate change having an impact, or genetic mutations?" Researchers even looked at ultraviolet light, mosquito sprays and old toxins in the soil.

After their discovery of the deformed frogs, the students conducted experiments, found experts, wrote papers, testified at the Legislature, even adopted a drawing of a deformed frog as the school logo.

But not everyone wanted answers, Helgen found, "particularly if, as we suspected, farm chemicals were at least partly to blame. And my bosses started telling me to pull back, that our agency was there to enforce existing laws, not find new problems."

In search of answers

Teacher Cindy Reinitz was new and not sure what to think that day 17 years ago when student Jeff Fish belly-dived across the grassy track At Ney Nature Center and came up with a frog, claiming it had a weird leg. Weird, or did he accidently break it?

"Then they started finding more, and we all knew something was wrong," said Reinitz, now a high school reading specialist in western Wyoming. "We found 22 frogs that day, and half had deformities. We didn't know what we had, but the kids wanted answers."

Reinitz called the MPCA and talked to Helgen. The students at the year-old Minnesota New Country School, built around student-led projects instead of formal classes, fired up their computers in search of experts.

"Mostly they either ignored us or didn't believe us," said former student Reta Lind, 29, who immediately began posting messages on Internet biological bulletin boards and listservs, a common way then for specialists to communicate.

With federal money from an Environmental Protection Agency grant for a wetlands study, Helgen and colleagues began to look for more deformed frogs.

Some scientists had been warning for two decades that frogs and other amphibians were declining worldwide, perhaps a harbinger of ecological degradation. The new findings heightened those concerns.

Days after the frog find at Ney Pond, the first article splashed across the front of the Star Tribune. Helgen started getting reports from around the country. Reporters from around the world streamed in.

"Oh, so it's the BBC today? The Disney Channel tomorrow? OK, just another day," recalled Nick Pollack, now 29 and head of public works in Henderson. "We weren't experts, but they seemed to think we were."

For a time, he went to the pond at 6 a.m. daily to haul water and sediment to the school for tadpole experiments.

"Our experience really changed me -- changed all of us," said Becky Pollack, Nick's wife and now director of the nature center. "The school and the frog project taught us how to think, how to work together to go after answers, take on big issues, speak and write and think outside the box. It really taught us about life, how to stay engaged even when there aren't nice, tidy answers."

The Legislature put up $700,000 to study the frogs and the MPCA came up with some more. But by the end of the decade, the agency was pressuring Helgen to stop the research, in part to conserve money at a time of tight budgets. By July 2001, agency officials called a halt to the work. Helgen left and was not replaced.

The agency is not apologetic.

"The investigation into potential causes became a nationwide question, which was much bigger than one agency could handle with limited research capabilities," said spokesman Ralph Pribble.

Still, he said, "The agency is proud of the work that Judy and other MPCA staff did with the frogs." He noted that the agency's website frog page is among its most popular, though not updated for 11 years.

'Nobody's collecting data'

"So here's what we think," Helgen said recently, fresh from an international conference where she met with other concerned researchers.

"There are multiple causes of deformation in frogs, and one is farm chemicals -- probably the major cause, because they can cause deformities and also weaken frogs, leaving them susceptible to injury and disease," she said.

There are fewer reports of deformed frogs, but also fewer frogs as wetlands shrink.

"Most deformed frogs die young," Helgen said. "Does that mean for a time, some widespread cause harmed many frogs -- maybe 20 percent or more instead of the usual zero to 2 percent -- and then it ended? We don't really know. Nobody's collecting data."

But there still are some who care.

Greg Pollack, the 10-year-old who caught the second frog, has become a passionate protector of damaged frogs. He has two now, including the one he caught -- impossible to say if it was deformed or injured.

"This guy can't survive on his own," he said. "I'll take care of him."

Warren Wolfe • 612-673-7253