Basic Cloud Seeding Concepts – March / April 2007
Southwest Hydrology
Cotton / Colorado State University
“Cloud seeding is increasingly being used for both water supply enhancement and weather damage reduction. In the West, cloud seeding is performed with the goal of increasing the overall precipitation into a watershed. Elsewhere, particularly the High Plains of the United States and Canada, it is used for hail suppression to reduce damage to crops and urban areas.”
Link to Full Article
It was in Pennsylvania that one of the first laws was passed with the intent of curbing possible harm to nature by changing the weather. In discussing the bill, which became the 1967 Pennsylvania law, one of its sponsors in the House of Representatives stated:
“Cloud seeding involves silver iodide, and silver iodide, Mr. Speaker, is
highly poisonous. AgI used in seeding falls
everywhere, on trees, in vegetation, roofs, people and in its
synergistic action joins with motor exhaust to become lead iodide…
Dry ice, CO2 also used in seeding, is equally dangerous, disrupting
the entire ecology of the planet.”
Legal Response to Environmental Concerns about Weather Modification
http://journals.ametsoc.org/doi/pdf/10.1175/1520-0450(1975)014%3C0681%3ALRTECA%3E2.0.CO%3B2
WEATHER MODIFICATION ACT OF 1972 / Pennsylvania
http://cwcb.state.co.us/legal/documents/statutes/art20title36.pdf
Silver Toxicity:
https://www.nature.nps.gov/hazardssafety/toxic/silver.pdf
“Hazards to fish, wildlife, and other non-human biota:
In fish and amphibian toxicity tests with 22 metals and metalloids, silver was the most toxic tested element as judged by acute LC50 values. In solution, ionic silver is extremely toxic to aquatic plants and animals. Among all tested species, the most sensitive individuals to silver were the poorly nourished and young and those exposed to low water hardness or salinity.”
Is Cloud seeding Harmful?
http://www.ranches.org/cloudseedingharmful.htm
The Office of Environment, Health and Safety, UC Berkeley, rates silver iodide as a Class C, non-soluble, inorganic, hazardous chemical that pollutes water and soil.(8) It has been found to be highly toxic to fish, livestock and humans.(6,7,8,9) Numerous medical articles demonstrate that humans absorb silver iodide through the lungs, nose, skin, and GI tract.(7,8,9) Mild toxicity can cause GI irritation, renal and pulmonary lesions, and mild argyria (blue or black discoloration of the skin). Severe toxicity can result in hemorrhagic gastroenteritis, shock, enlarged heart, severe argyria, and death by respiratory depression.(8)
Moreover, a key manufacturer of silver iodide for weather modification, Deepwater Chemicals, warns of potential health effects of silver iodide in their Material Safety Data Sheet as follows:
Chronic Exposure/Target Organs: Chronic ingestion of iodides may produce “iodism”, which may be manifested by skin rash, running nose, headache and irritation of the mucous membranes. Weakness, anemia, loss of weight and general depression may also occur. Chronic inhalation or ingestion may cause argyria characterized by blue-gray discoloration of the eyes, skin and mucous membranes. Chronic skin contact may cause permanent discoloration of the skin.(10)
Under the guidelines of the Clean Water Act by the EPA, silver iodide is considered a hazardous substance, a priority pollutant, and as a toxic pollutant.(10)