MOSCOW -- Only last month, Vil S. Mirzayanov was sitting in jail charged with betraying his country's secrets. Yesterday, he was invited to address parliament, where his comments drew a respectful hearing.

It was a long way from the early hours of Oct. 22, 1992, when Dr. Mirzayanov was awakened by KGB agents pounding on his door and hustled off for questioning.

He was accused of revealing state secrets for disclosing that Russia had continued chemical weapons research well after it told the world it had stopped.

Earlier this month, the charges were dropped, and the government apologized to Dr. Mirzayanov, a chemist.

Yesterday, he offered expert testimony to the State Duma, which was discussing plans for destruction of chemical weapons.

"I'm thankful I can speak to you from the rostrum without handcuffs," Dr. Mirzayanov told the Duma before offering a calm,

detailed analysis of weapons disposal options.