According to the Department of Health's report on city pesticide use in 2011, Roundup, the weed-killing key to Monsanto's agribusiness empire, is the city's most heavily used liquid herbicide.
Roundup is Monsanto's signature blend of glyphosate—a compound that works by disrupting an enzyme key to plant growth—and other ingredients to destroy weeds.
Monsanto's Roundup brand alone was applied by the city nearly 500 times last year—about a dozen bathtubs' worth in undiluted form, according to DOH's annual pesticide figures—mostly via the Roundup Ultra formulation, a more concentrated version of the original.
The Parks Department, responsible for most of the city's Roundup use, declined to answer my request for a description of where it uses Roundup and how much, though did confirm its use in iconic locations like Central, Prospect, and Riverside parks. Roundup applications are done "at various locations throughout the city system under careful supervision and in very limited quantities," was the extent of Parks' disclosure on the subject.
Parks also declined my request for a sample of the warning sign or safety protocols that it posts around areas where Roundup is sprayed, though signs from previous years noted that Roundup applications, at sites like Central Park's Turtle Pond and Metropolitan Museum grounds, were done at 4 a.m. Parks didn't answer my question about how long it warns passers-by away from sprayed areas.