"The high levels of Ba stemmed from local quarrying for Ba ores and/or use of Ba in paper/foundry/welding/textile/oil and gas well related industries, as well as from the use of Ba as an atmospheric aerosol spray for enhancing/refracting the signalling of radio/radar waves along military jet flight paths, missile test ranges, etc."
Purdey, Mark, Chronic barium intoxication disrupts sulphated proteoglycan synthesis: a hypothesis for the origins of multiple sclerosis
in: Medical Hypotheses, Volume 62, Issue 5, May 2004, Pages 746-754
http://www.sciencedirect.com/science/article/pii/S0306987704000222


Source: http://www.geoengineeringwatch.org/lab-tests/