Bill Lueders has an article about pesticide being sprayed near schools. I contacted school board members, and they were very nice about answering my questions. (That's not surprising though.)
Maya Cole forwarded my questions to a member of the school business services who said that the chemical used wass glyphosate, also called Roundup - though Roundup contains other so-called "inert" ingredients besides glyphosate, which are toxic themselves. Roundup is made by Monsanto and is commonly used. Not commonly known is how toxic it is.
About glyphosate (Roundup), according to the manufacturer - Monsanto - up to 140 days are required for half of it to break down. When used in agricultural settings, residues of glyphosate were found in vegetables planted 1 year after the glyphosate treatment.
Glyphosate is acutely toxic to humans. 3/4 of a cups ingested can be lethal - of course much less would be needed for a child. Symptoms include eye and skin irritation, lung congestion and erosion of the intestinal tract. In 1997 Roundup, the Cal. Pesticide Illness Surveillance Program found Roundup ranked as the highest cause of pesticide-induced illness or injury to people in California.
It is not only the active ingredient (glyphosate) that is dangerous, but several "inert" ingredients as well. A letter in Nature (scientific papers, peer-reviewed) stated that POEA. one such chemical that constitutes 15% of Roundup, was responsible for 9 deaths in Japan.
A study by eminent oncologists Dr. Leonard Hardell and Dr. Mikael Eriksson of Sweden, has revealed clear links between glyphosate to non-Hodgkins Lymphoma - a form of cancer.
The "weeds" are not toxic and some can be used for food and are quite healthy. Here's an article about that.