Banned Pesticide Used in Marin

A weedkiller was used by contractors that includes a cancer-causing chemical was used in June during construction of a bike lane project on Alameda del Prado in Ignacio in violation of county pesticide law, officials said, adding that there is no cause for alarm. Although the substance is approved by the federal Environmental Protection Agency and routinely used elsewhere, it is not allowed under county pesticide rules.

In a written announcement, the county said workers for Bauman Landscape applied 100 pounds of "a pre-emergent weed control product, Ronstar G (EPA Reg. No 432-886)," a substance banned by the county's Integrated Pest Management program.

News of the Alameda del Prado incident surfaced as county officials celebrated completion of the bike path project with a ceremony on Monday. The construction cost about $950,000, with all but $100,000 coming from the Federal Highway Administration.

Paul Apffel, a pesticide watchdog who last year blew the whistle on county staff violations of pesticide rules, lauded the county for bringing the Ignacio violation to light, calling it a "failure of supervision" of contractors who apparently used a substance commonly applied to golf courses.

The federally-approved substance was applied to soil in median strips, then covered with mulch, making human contact with it unlikely.

County officials, who said use of the product was disclosed when they reviewed a work report, promptly posted a notice of violation on the county website but contended n the other hand, the county notice added that "Ronstar G is listed in Proposition 65 as a product that contains a chemical known to the state of California to cause cancer; Oxadiazon 19666-30-9 and Naphthalene 91-20-3."