Newly released army documents prove that two American POWs wrote encoded messages to Army intelligence after their 1943 visit to Katyn, pointing to Soviet guilt for the 1940 massacre Government cover up began during WWII when the U.S. needed the Soviets to defeat Germany and Japan After decades of denial, Soviets confessed to the massacre in 1990
"The CDC update changed the lethal exposure from 100PPM to 100,000PPM. The lethal exposure level had remained the same for 17 years before the CDC decided to update the number just prior to the derailment, where highly toxic chemicals spilled or were burned off, leaving a chemical stench in the air nearly two weeks later."