Ducks that landed on the ponds burned their feathers on the toxins. Poisons from chemical weapons seeped into the groundwater, damaging crops and ruining wells for drinking water. Sarin nerve-gas bomblets turned up in the dirt and rubble. Fish from the lakes could not be eaten because their mercury levels were so high.

That's the kind of damage that occurred at at the Rocky Mountain Arsenal, where the Army made nerve gas until 1957, napalm until 1968, and deactivated such weapons until 1984 - all just eight miles northeast of downtown Denver.

On top of that, Shell used the site to make pesticides, some so lethal they were later banned.

Now, Colorado Attorney General John Suthers wants to reopen a 22-year-old lawsuit seeking cash compensation from the Army and Shell for natural resource damages.

At a legislative hearing on the topic Wednesday, Suthers was asked if the amount of the damages could reach $100 million.

His reply: "That's certainly moderate."

Since collecting such a sum may be difficult, said Suthers' spokeswoman, Kristin Hubbell, the state is in negotiations, hoping to settle out of court.

Nevertheless, Suthers asked the legislature on Wednesday for $1 million to pay the state's legal expenses in pursuing the case and warned that he may be back asking for similar amounts for up to 10 more years.

Even if it costs $10 million to win the lawsuit, Suthers said, it would be a good investment for the state.

The 27-square-mile arsenal, a Superfund site north of the old Stapleton Airport, has seen 5,000 of its least-contaminated acres converted to a wildlife refuge. But more than 10,000 acres still are being cleaned up as part of a $2.2 billion job expected to continue to 2011.

In comparison, the notorious Rocky Flats nuclear weapons plant on the northwest side of Denver, torn down at a cost of more than $6 billion, "did not make anywhere near the mess" as the chemicals at the arsenal, said Senior Assistant Attorney General Vicky Peters.

The arsenal, she said, dumped chemicals on the ground and into lake-sized unlined basins that leaked into the groundwater.

"Contaminated soils blew all over the place," she said.

This toxic stew began brewing in 1942 when the arsenal was created to manufacture mustard gas, which causes blistering, blindness and respiratory problems.

Later, the arsenal grew into a sprawling plant making far more lethal sarin nerve gas. That gas, never used by the United States, causes victims to stagger and jerk as their muscles convulse. They die of respiratory arrest.

As late as 1984, sarin was drained from munitions on the site and chemically deactivated. But six sarin bomblets were found in rubble on the site just five years ago.

Much of the contamination is being buried in a landfill on the site that is in part triple-lined, Peters said.

"The worst of the worst is going in there," she said.

Some 750 million gallons of groundwater are treated every year at the arsenal, according to its Web site. Owners of nearby contaminated wells had to be provided with alternative sources of water, Peters said.