Man allegedly stored cyanide in Chicago subway

Joseph Konopka is shown in a previous court appearance in Wisconsin.

CHICAGO, Illinois (CNN) -- Federal authorities Monday charged an unemployed man with possession of chemical weapons for storing more than a pound of powdered cyanide in an underground passage that is part of Chicago's subway system. But officials said the arrest was not related to any terrorism.

"It's a serious situation," said U.S. Attorney Patrick Fitzgerald. "But we don't want to blow it out of proportion so that people are afraid to ride the subway."

FBI spokesman Ross Rice downplayed any terror links to the case. "This is not a terrorist plot," Rice said. "I don't think it's a big deal."

RESOURCES Criminal complaint: US v. Konopka  (FindLaw document PDF)

The charge unfolded after Joseph Daniel Konopka, 25, was arrested Saturday by University of Illinois at Chicago police for allegedly breaking into tunnels beneath the UIC Education Building, authorities said Monday.

Upon his arrest, UIC police recovered a vial containing powder that lab tests identified as sodium cyanide/sodium carbonate, poisons that also have industrial uses, officials said.

The school's police called the Chicago Police Department, which found that Konopka was wanted in Wisconsin for failing to appear on state charges alleging vandalism against utility systems, the Department of Justice said in a news release.

The suspect, who has no known address and told police he was unemployed, was then turned over to the FBI.

The FBI's Rice said Konopka told agents that he had been living in the subway system for several weeks.

FBI agents, the Chicago police and Fire Department hazardous materials teams searched Chicago Transit Authority tunnels over the weekend, shutting the Blue Line on Sunday, authorities said.

In an underground storage room whose lock Konopka had changed, authorities found seven containers marked as holding various chemicals, the officials said.

Two containers were marked as containing cyanide compounds, stored among other belongings in an underground Chicago Transit Authority, they added.

Tests determined Monday that one held 0.9 pounds of sodium cyanide and the other held nearly 0.25 pounds of potassium cyanide, the release said.

Officials have found no work-related reason for Konopka to posses the cyanide, which can be used to clean metal. Both compounds can kill humans if ingested or converted to gas.

Konopka also told the FBI he had keys to various CTA substations, and that he had been involved in acts of damage to power, water, cell phone and sewer facilities in Wisconsin, Rice said.

A spokeswoman for the Door County Sheriff said she would not have a comment until Tuesday.

Konopka faces a preliminary hearing in U.S. District Court on Wednesday morning.

If convicted, possession of chemical weapons carries an indeterminate prison term, with no set maximum sentence, as well as a fine of up to $250,000, according to a statement from the FBI.

"The system worked, and that's the bottom line," said Chicago Police Superintendent Terry Hillard.

Chicagoans should not fear riding the subways Tuesday, he said. "Why should they be scared? At no time was the safety of any citizen in this city compromised, none whatsoever."

Asked what Konopka might have been planning to do with the compounds, Hillard said, "I'm not a psychiatrist."

Officials did not say how long the chemicals might have been stored underground.

"Cyanide is a dangerous chemical. That's why it is a crime to possess it without a peaceful purpose," said U.S. Attorney Fitzgerald.