The trees surround this tiny farm community deep in the San Joaquin Valley. The chlorpyrifos -- banned for domestic use since 2000 yet still used widely on crops -- falls like a lethal mist, first paralyzing then killing insects seeking a portion of Tulare County's $4.3 billion in agriculture sales.
But the nights are hot, the fans are powerful, and the mist travels.
And so, invariably, swamp coolers straining against the smoggy heat pull the poison into Lindsay's homes.
Some residents smell the pesticide's slightly sweet, slightly acrid odor and figure it will pass. Some complain of headaches and nausea. Some chalk up the asthma and balky breaths to another day in the worst air in the nation. Many will never notice.
But all are likely breathing it.
Initial results of a pilot program in this Central Valley farming community suggest that no matter the location, Lindsay's residents have more chlorpyrifos in their bodies during the monthlong spraying peak than the U.S. Environmental Protection Agency considers acceptable for pregnant and nursing women.
The program, a collaboration with Pesticide Action Network, the nonprofit environmental research firm Commonweal, and the community group El Quinto Sol de America, tested the urine of 12 adults in various locations throughout the town during peak spraying season last summer. All but one had chlorpyrifos concentrations above the EPA's recommended threshold of 1.5 parts per billion, equivalent to a grain of salt seasoning 150 pounds of mashed potatoes.
The results pair with air monitoring data, also done by the group, that show for three years running chlorpyrifos in the air in town and near schools exceeded the EPA's acceptable level for short-term exposure.
The results for the first time shed light on a problem residents suspected but could not prove: that a pesticide banned for household use was drifting off nearby fields and into their homes, with unknown long-term health consequences.
"The most important thing is we don't know," said Ana Gonzalez, who lives in one of the six houses where air was sampled. "The fear, the danger of having the pesticides right near us -- we could fight against something we could see: A robber, a poison right here at home. But this we can't see."
The results of the study, released today, are notable on several fronts.
Yet commercial growers can legally apply it to plants abutting homes within one-quarter mile of a field or orchard. Advocates seek a quarter-mile spray zone as a buffer.
California is in the midst of establishing the first-ever statewide program to probe its residents' blood, hair and urine for various chemicals. The program will provide a benchmark of sorts for the state, but many advocates want more.
They want the program to test communities facing environmental health threats. But industry has balked.
Margaret Reeves, a senior scientist at the Pesticide Action Network and the Lindsay program's coordinator, said, "The fact that we can demonstrate that it's out there and that it's in their bodies and that it's associated with all these known health effects gives power to the community's demands. It makes them look real reasonable."
The state takes these concerns seriously, said Glenn Brank, spokesman for the California Department of Pesticide Regulation.
The group's air monitoring data is in line with other levels the department has seen in other communities. "We do not see an imminent health threat from the chlorpyrifos based on the levels we've found in the air," he said Tuesday.
But its presence in so many air samples has prompted the agency to take a harder look. It has launched its own pilot study in the Fresno County community of Parlier, which suffers from some of the valley's worst air quality. Those results should be ready later this fall, Brank said.
"We do see ongoing exposures at very low levels," he added. But "as of now, we don't see anything from the air standpoint that represents a concern."
Irma Arrollo arrived in Lindsay from Mexico 19 years ago. She spent her first two months in America in her house, too terrified of authorities to go out. Eventually, she started helping in her son's school and learned other immigrants were in even worse shape, unable to read or write and with little support.
She founded El Quinto Sol a decade ago to help Lindsay's immigrants adjust to America and to fight for their health and rights.
The lessons they have learned here apply to any community fighting against poor environmental health, she said: Cities have diesel pollution. Pesticides don't just drift only over Lindsay.
"This is a crisis," she said. "People don't listen to us when we say we have these concerns."
Farmers spread about 2 million pounds of chlorpyrifos, often sold as Dursban, over 1.7 million acres in California in 2005, mostly on cotton, oranges and walnuts. Humans pass it quickly, but the U.S. Centers for Disease Control and Prevention estimates 75 percent of all Americans have some in their blood, suggesting exposure is continuously occurring and widespread.
Side effects of breathing the chemical are similar to nerve gas, a chemical cousin: dizziness, nausea, inability to concentrate, numbness or tingling in the limbs.
Meanwhile, more than half of Tulare County's children attend a school that sits within a quarter mile of a field or a dairy, a figure educators put on par for most rural areas.
Sunnyside School District sits five miles south of Lindsay. The "district" is really a dusty collection of buildings and turf hemmed on all sides by agriculture: oranges to the east, north and west, olives to the south. Superintendent and principal Steve Tsuboi has spent all his life in Tulare County. The biggest change, he notes, is that the Sierra foothills, less than 10 miles east, have faded from view, obscured by hazy smog.
The growers, he said, are "pretty good" about not spraying while children are around.
But Arrollo recounted the day last November when students invited their grandparents to school. A grower was spraying nearby groves that day -- without many required safety precautions, Arrollo later discovered. A few grandparents felt dizzy. One or two fainted, she said.
"Children in Tulare County aren't good in education," she said. "They don't learn fast. The have low test scores."
In a region where one out of five children have asthma, where the sky is so smoggy that nearby hills have disappeared from the horizon, chlorpyrifos is just a tiny part of the problem. The chemical accounts for 2 percent of nearly 18 million pounds of pesticides applied in the county annually, and identifying the community's chemical body burden won't cure any woes, Arrollo said.
But it has emboldened residents. And that's the point, activists note.
Ana Espinoza was eight months pregnant when she tested for chlorpyrifos. Her first reaction upon getting the results, she said through a translator, was to say to her husband, "Let's get out of here.
"Then I thought going away is not going to solve the problem."
Today little Ximena is a year old. She's got two pigtails, pierced ears, and a sibling on the way: Ana is pregnant again.
A few months ago Ana, her husband and Ximena moved from their home in Lindsay to a mobile home so close to the fields they can pick walnuts from their porch.
"I moved, but I didn't escape it," she said with a grin. "It's better to get united with the community. It can get better.
Staff photographer Ray Chavez contributed to this story. Reach Douglas Fischer of the Oakland Tribune at email@example.com or 510-208-6425.