http://www.ksla.com/Global/story.asp?S=7339345&nav=0RY5
some excerpts

KSLA News 12 had the sample tested at a lab. The results: A high level of barium, 6.8 parts per million, (ppm). That's more than three times the toxic level set by the Environmental Protection Agency, or EPA.
We discovered during our investigation that Barium is a hallmark of other chemtrail testing. This phenomenon even attracted the attention of a Los Angeles network affiliate, which aired a report entitled, "Toxic Sky?"
There's already no shortage of unclassified weather modification programs by the government. But those who fear chemtrails could be secret biological and chemical testing on the public point to the 1977 U.S. Senate hearings which confirmed 239 populated areas had been contaminated with biological agents between 1949 and 1969. Later, the 1994 Rockefeller Report concluded hundreds of thousands of military personnel were also subjected to secret biological experiments over the last 60-years.
KSLA News 12 discovered chemtrails are even mentioned by name in the initial draft of HR 2977 back in 2001, under the Space Preservation Act. But the military denies any such program exists.
It turns out, until just nine years ago the government had the right, under U.S. law, to conduct secret testing on the American public, under specific conditions. Only a public outcry repealed part of that law, with some "exceptions."

Story by Jeff Ferrell