San Francisco, Calif. — In late June, the California Department of Food and Agriculture canceled plans to spray a pheromone that would disrupt the mating of light brown apple moths, an invasive pest that, officials say, could cause over $100 million in damage to crops.

The state would have used airplanes to spray the pheromone over densely populated parts of the San Francisco Bay area at night. “The change of course comes after thousands of citizens questioned the safety and effectiveness of the spraying program,” according to an article in The San Francisco Chronicle. One might argue, though, that paper itself played an important part in facilitating the change.

Beginning in February and throughout the spring, the Chronicle published a series of articles about complaints that the pheromone had caused health problems—such as coughing, muscle aches, and headaches—when it was sprayed over two counties south of San Francisco last fall. The articles pitted local activists and scientists, who argued that the state had not adequately studied the impact of spraying, against government officials and scientists, who insisted that the spraying was safe. Soon after its first news article on the plan, the Chronicle published an editorial stating that it wasn’t buying the government line:

The state will have to do a much better job of explaining its methods than it has so far at a handful of local meetings.

If time is critical in stamping out this pest, then Sacramento must do more to describe its plans and the foreseeable risks. The Bay Area needs convincing.

Unfortunately, the Chronicle helped impede any meaningful (and totally warranted) scientific debate about health and environmental impacts of spraying by ignoring information that was, in fact, already available. In the spring and summer of 2007, the paper published several stories about the moth’s discovery in California, including a number of pieces about a group of international scientific experts convened by the U.S. Department of Agriculture to offer advice on how to deal with the moth. (The panel, called the “technical working group,” recommended eradication.)

The state, meanwhile, had prepared several publicly available documents. One was a twenty-page report to the state legislature detailing when, why, and how it had conducted spray programs in Santa Cruz and Monterey counties. Another was a ten-page statement, from the state Department of Pesticide Regulation and the state Office of Environmental Health Hazard Assessment, that analyzed the toxicity of the pheromone sprayed in those counties and investigated health complaints following the spraying (which got a brief mention in the Chronicle’s editorial). Others included the results of environmental toxicity tests on the pheromone and the summaries of meetings of the technical working group.

What was the problem with that information? It came from the government. And as the Chronicle’s environmental reporter, Jane Kay, wrote in her first apple-moth story: “Further complicating the issue is that some residents say they simply don’t trust the government information.”

Judging by its coverage, neither did the Chronicle. After years of stories about chemical companies and bureaucrats pressuring government scientists to bend data, that’s no surprise. Indeed, right in the middle of the apple moth affair, the Chronicle published an unrelated story reporting that the Government Accountability Office, a watchdog agency, had found that “the White House’s budget office, the Pentagon and other agencies had delayed or blocked efforts by the Environmental Protection Agency to list chemicals as carcinogens by requesting more research or more time to review the risks.”

The truth about how chemicals, including pheromones and pesticides, are regulated (or unregulated, as it were) in this country is fairly scary. State officials say there’s no proof the pheromone causes harm, and they’re right. There’s also no convincing proof it doesn’t.

According to the EPA, moth pheromones have such a low toxicity that existing tests, which found that they are adequately benign, can be applied to all new varieties, even if they contain different active ingredients. But the agency doesn’t require that the inert ingredients be tested at all, or even that manufacturers list them. (The state didn’t research the inert ingredients in this particular formulation of Checkmate until ordered to do so by a judge, after they’d already been spraying for several weeks.) It also doesn’t mandate testing of the active ingredients’ potential to create long-term illnesses, even though the spray programs often lead to chronic exposure. As Kay pointed out in a number of her articles, there’s still no conclusive safety testing on the apple-moth-specific form of Checkmate used in Santa Cruz and Monterey.

“When you write that in stories people are just outraged,” Kay told me, “it’s just the first time they’re realizing that chemicals aren’t as carefully monitored as they might think.”

Eric Simons is the author of Darwin Slept Here and a freelance journalist based in San Francisco.