"They have to be more specific than that," he said. "It ate the side of this thing apart. Don't tell me there wasn't something wrong with the mixture of chemicals."

PSC spokeswoman Barbara Smith said that besides the words describing the material, the manifest contained coding that described its properties, as required by regulations. The car also had a diamond-shaped placard on its side with information about the contents, she said.

Three rail cars were to be shipped at the same time, she said. Two arrived safely in Ohio so the hazardous waste could be disposed of. But for some reason, she said, the third was taken not to Ohio but to Kennecott's operations in Utah.

Another oddity, Smith said, is that this third car was picked up for transport on Feb. 21, but PSC did not release it until Feb. 23.

The combination of ammonia and acids struck Richard P. Steiner, a chemistry instructor at the University of Utah, as strange.

"Ammonia is a base and all the others are an acid. All the others are incompatible" with ammonia, Steiner said. "That would cause a chemical reaction."

According to the company records, Smith said, the material inside the tank was "a transportable hazardous waste." But the company is continuing its investigations, working with Union Pacific and Kennecott, she added. Louie Cononelos, Kennecott's director of government and public affairs, said hydrofluoric acid, nitric acid, hydrochloric acid, ammonia, acetic acid and phosphoric acid should not have been in the tanker.

"All of our sulfuric acid tank cars are equipped with a liner that is called a phenolic liner. That is a coating that is applied and then heat-treated, that coats the entirety of the tank."

The liner is designed to protect the tanker's steel walls from corrosion by sulfuric acid, which is a by-product of Kennecott's production process.

If the wrong chemicals were in the tank they could have damaged the liner, "which of course would have compromised the integrity of the vessel," he said.

He believes the contents reported in the tanker "do not follow the manufacturer's specifications for that phenolic coating."

Asked if Kennecott had received a manifest with the car's contents before the incident, Cononelos said, "I don't know." As of press time Tuesday, he had not said whether the company received the manifest before Sunday.

Smith said PSC records show the company faxed Kennecott a manifest listing "mixed acids" on March 1.

A broker leased the tank from Kennecott and then to PSC, she said.

If the tank logo said "sulfuric acid," should other material have been inside?