Mike Bauman, 57-year-old owner of Bauman Landscape in San Francisco, said his firm had no idea it was breaking county regulations when it applied two pounds of the weed killer Ronstar G to soil in Ignacio median strips as part of a bike path project this summer.

"No one told us that we couldn't use it," an exasperated Bauman said, adding he first learned of the regulations when his staff was asked after the job was over about what chemicals were used.

"Why didn't you tell us ahead of time?" Bauman wondered. "It's not in the specifications. ... They are so screwed up over there, it is amazing. We've been working in the county for 30 years and it's gotten worse and worse."

Bauman's assertions raised questions about county enforcement of pesticide and herbicide laws officials have trumpeted as tougher than those imposed by the state and federal governments. Paul Appfel of Corte Madera, a pesticide watchdog who last year blew the whistle on 269 violations of pesticide rules by the county's own staff, called the latest incident a "failure of supervision" by the county of its contractors.

"If there are restrictions, they should put it in the contract specifications," Bauman said, adding he has another pending job in Marin, this one dealing with landscaping at Marin Center. "We've just given them a (requestfor information) asking what they want us to do."

Ronstar G was part of the Marin Center project until the issue surfaced, Bauman said. "Is there an alternate they want us to use?" he asked.

County Public Works chief Farhad Mansourian, responding to Bauman's criticism, noted that existing specifications already compel contractors to follow the law, instructing them to obey local policies, while not spelling them all out.

"It is not our job to hold their hands and ask 'Do you know what you are doing?'" Mansourian added. "This is a product banned by the county. The specifications say compliance with all local laws."

Bauman said it is a shame that one of the richest counties in the nation has "the worst-looking landscaping" because of a refusal to use products that curb weeds.

"They'll have to hand weed it all the time. They'll never do it," he said, creating a situation in which a weed-whacking crew moves in to cut back the overgrowth every six months. "There's no common sense anymore. They just let all the landscaping go. Within six months, the place looks like garbage. It's crazy. It's sad."

As a result of the flap, public works staff will revise contract specification documents to ensure adherence to policy requirements. Assistant Public Works Director Saaid Fakharzadeh said future contracts will point out pesticide and herbicide policy, and that scofflaws will face a $200 fine. No fine was listed previously.

Ronstar G, approved for use across California by the Environmental Protection Agency, is available over the counter at irrigation supply stores and poses no harm when used to prevent weed germination in median strips, Bauman said.

"You'd have to eat the whole bag to get sick," he said.

County officials promptly publicized a notice of violation after learning a product not approved as part of pesticide policy was used. They agreed there was little reason for alarm since, according to a notice, "Ronstar G is a product approved in California for this type of application and it is commonly used in the landscape industry for weed control; it was applied in accordance with label requirements and EPA regulations."

On the other hand, the county notice added that "Ronstar G is listed in Prop. 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." In addition: "This product contains a chemical known to the state of California to cause birth defects or other reproductive harm, Oxadiazon 19666-30-9."

The county's strict pest and weed management ordinance declares no county department shall use "any ingredient classified by the U.S. Environmental Protection Agency as a human carcinogen, probable human carcinogen, possible human carcinogen, reproductive toxin or developmental toxin." The law allows exceptions but requires the approval of the county Integrated Pest Management Commission, and official policy lists acceptable products for use.