Seven years ago, when west Modesto resident Lori Wolfe heard there was barium-laced soil piled along Kansas Avenue through her neighbors, she decided to take a sample of her family ranch’s well water to a lab.
The test confirmed there was barium in the dirt – and at elevated levels. Her Wood Colony ranch, which produced almonds and now alfalfa, sits about three and a half miles from where the stockpiles from a former chemical plant stood and where Highway 132 now runs.
Though the barium level in her well was below the World Health Organization’s guideline, her family switched to bottled water anyway.
“I wouldn’t move off that ranch, this place is a part of me, a part of my family,” said the 68-year-old Wolfe, “but I’m not going to drink the well water either.”
Wolfe is one of many west Modesto residents who spent years asking what the dirt left behind by the former FMC chemical plant meant for their health. The Highway 132 bypass opened in 2022 on top of the defunct west Modesto chemical plant’s waste ponds just west of Ninth Street and north of Kansas Avenue.
Regulators have long insisted that the stockpiles and soil left behind do not pose a public health risk. Caltrans and the state Department of Toxic Substances Control (DTSC) say the soil is now sealed, monitored and safe.
Still, the mounds sat fenced but uncovered for more than half a century. Wolfe and her neighbors say their questions were heard but never answered by officials despite their assurances.
Now a local environmental justice group, Valley Improvement Projects (VIP), is starting its own testing. Meanwhile, the state is still coming for Wolfe’s land through eminent domain, seeking almost four acres of her family’s ranch for an extension of the project.
A West Side legacy
From the 1930s to the 1970s, the Food Machinery and Chemical Corporation (FMC) plant processed barite and celestite ore near what is now the Highway 99 and Kansas Avenue interchange. The ingredients were used for greases, lubricating oil and pigments. Liquid waste went into unlined ponds that left a residue of barium and other metals in the pond bottoms and the soil beneath.
Barium is a silvery-white metal that takes on a silver-yellow color when exposed to air, and has different compounds that have varying effects and levels of threat.
In 1961, the state bought part of the FMC property, including some of the ponds, to build Highway 99. Pond residue and excavated soil were piled south of Kansas Avenue in three mounds, about 20 feet high and totaling 160,000 cubic yards.
Some of that soil tested at barium levels up to 72,000 milligrams per kilogram, along with elevated lead, according to the site’s state-approved maintenance plan. That means barium, specifically barium sulfate, holds 7% of the soil by weight.
The U.S. Environmental Protection Agency uses 15,000 milligrams of barium per kilogram as its standard screening level for residential soil. Above that, regulators take a closer look at a site, testing further and assessing whether people could be exposed. At about 46,000, the agency considers taking action, according to EPA screening tables. That doesn’t always mean removing the soil: it can be capped or covered, its use restricted and the site monitored. Those are the steps the state took at the Modesto stockpiles.
The highest stockpile readings were well beyond both levels. State regulators say the soil still poses little risk, for several reasons.
Most of the barium is barium sulfate, the same compound patients swallow for X-ray exams, which the body barely absorbs, according to the cleanup plan. However, in 2006 tests done at the site found that some samples released soluble barium above the state’s hazardous-waste threshold.
Barium sulfate passes through the body largely unabsorbed. Forms that dissolve can enter the bloodstream, where barium interferes with the potassium the heart and muscles need to function.
Sampling along the fence line in 2012 found barium at the edges of the stockpiles fell below residential screening levels, suggesting it had not spread far, the project plan says. Plus more than a decade of groundwater testing showed the metals had not reached the water table, according to the Department of Toxic Substances Control.
With the soil now sealed beneath pavement and retaining walls, the department says, there is no way for people to touch, breathe or swallow it. A state land use covenant bars homes and schools on the site and forbids digging without approval. The department’s health risk assessment found the site containment protected nearby residents.
But, residents and advocates say those reassurances don’t account for the half a century the mounds sat uncovered.
“They put it on that corridor because Caltrans owned it,” said Gavin Bruce, a program manager with Valley Improvement Projects. “So they said, ‘Oh, we’ll just pile it right here and we’ll figure out what to do with it later.’”
A 2003 state assessment flagged the then uncovered stockpiles, and testing from 2004 to 2006 confirmed the contamination. The surrounding census tract ranks in the 90th to 95th percentile statewide on CalEnviroScreen, California’s measure of pollution burden and community vulnerability.
Wolfe, who spent most of her life on the east side of Modesto until she moved to the west as an adult, said her neighbors told her the toxic chemicals that were buried on the site were never a secret.
“Everybody’s kids remember playing on those stockpiles when they were young. They used the dirt piles for dirt bikes, even though they weren’t supposed to,” she said. “Matter of fact, Graphics Lane, where the highway is, used to be called Barium Lane by the locals.”
The less expensive cleanup option
The state’s 2018 cleanup plan estimated that hauling the soil to landfills would cost about $21.5 million, compared with about $1.6 million to seal it inside the highway. The plan acknowledged that complete removal “may be the most acceptable to the community,” but went with the cheaper encapsulation method instead.
Caltrans says the decision was made with DTSC and the Central Valley Regional Water Quality Control Board, which oversaw the work.
“It was determined to be the safest and most practical approach,” Erin McQueary, public information officer for Caltrans District 10, said in an email statement. “Excavating and hauling the soil away would have created added risks, including exposure for the public and workers.”
Work on the first phase of the highway began in October 2019. In early 2020, crews removed the stockpile east of Highway 99 and hauled about 3,075 truckloads into the embankment to the west.
Crews kept digging until samples fell below 1,000 mg of barium and 80 mg of lead per kilogram of soil, targets at or below the levels regulators use to screen soil where people live, according to Caltrans’ 2022 completion report.
Now Caltrans, in cooperation with Stanislaus County, proposed to expand the highway 7.2 miles of Highway 132 in the coming years, two miles west of Modesto.
The embankment now seals the stockpiles beneath pavement and behind retaining walls, with clean soil cover on unpaved areas, according to DTSC. That prevents contact with the soil and keeps rain from carrying contaminants to groundwater, the agency said.
Valley Improvement Projects notes that the north slopes are covered by soil and vegetation rather than concrete, and that no liner separates the old stockpile from the native soil beneath it. The group plans to begin its own soil testing again at their next meeting on Oct. 21, and will take those results to regulators if warranted.
“If monitoring ever indicates a concern, DTSC will act immediately to protect public health and the environment,” said Alysa Pakkidis of the DTSC Office of Communications in an email statement.
Juan Telles, a Valley Improvement Projects coordinator and Modesto City Council candidate who lives five miles from the corridor, points to the gaps in the encapsulation.
“It’s like these soils are half contained,” he said. “We were told that the metals won’t reach groundwater, but that’s simply what we’re being told.”
The nonprofit group began stormwater testing of the site for barium in 2012. Telles, who grew up in west Modesto, said 2024 results showed the highest levels of barium they had ever recorded.
“I’m not a scientist, but in my opinion, I think it was because of our intense atmospheric rivers,” he said. “We had a lot of water, and I believe that the barium was seeping into the stormwater.”
When the risk rises
Barium’s danger depends on its form. Barium sulfate passes through the body harmlessly and is used in X-ray imaging. But forms that dissolve easily can cause changes in heart rhythm and, at high doses, damage organs including the kidneys. Soluble compounds include barium chloride, barium nitrate and barium hydroxide, according to the federal Agency for Toxic Substances and Disease Registry.
“It’s the water-soluble form of barium that’s toxic. The insoluble form is not too bad,” said Qi Zhang, a UC Davis Environmental Studies professor who studies how pollutants disperse in the air.
Since 2006, state consultants have tested the barium at the Modesto site and found it was mostly barium sulfate, the safer and harder to dissolve form. But when they soaked samples in water to see how much barium would dissolve, nine of 33 samples released more than a state limit used to identify high levels in hazardous waste.
When the soil is dug up or agitated, Zhang said, “small particles can enter the air.” Most of that dust is heavy and settles quickly. But even barium in its safer form, barium sulfate, can change once it’s airborne.
“Even if it’s the insoluble form that’s in the soil, when this dust goes through atmospheric processing or chemical reactions in the atmosphere, they can be converted into water-soluble form,” Zhang said.
Pollution from vehicle exhaust produces nitric acid, which can react with barium sulfate, turning the chemical into barium nitrate – the much more water soluble form. That’s why the concern centers on digging and moving contaminated soil.
“In terms of the potential for community exposure, it’s likely to be a concern during the [excavation],” Zhang said.
That worries Jessica Coleman, who runs the Modesto Children’s Garden on five acres near Maze Boulevard and just blocks away from Highway 132.
“We don’t want our kids … eating food that has pesticides on it at all,” she said. Coleman emphasizes that pesticides and chemicals are never used at the garden, and they instead utilize natural pesticides and herbicides with different flowers and plants.
So, the thought of being in close proximity to toxic chemicals is scary, said Coleman, and the opposite of what she wants for her garden. After Valley Improvement Projects showed her where the soil is buried, she began worrying about any future digging.
“It sounds like it has the potential to really cause harm,” she said. “I consider that an emergency.”
Air monitoring during the 2020 earthmoving found dust, barium and lead below project limits, Caltrans’ consultant reported.
“Dust controls are effective but never 100%,” Zhang said. But he also urged residents not to fixate on one metal: “Community-level barium exposure, in my opinion, is likely less important compared to other toxicants in this soil like lead, which can be dangerous even at small levels.”
State consultants found lead in all three stockpiles at levels above what occurs naturally in nearby soil, according to the state’s 2018 cleanup plan for the site. Most of the soil was well below 80 milligrams per kilogram, the residential screening level California regulators use to decide when lead in soil needs a closer look, the plan says.
Of 278 samples, only two soil samples exceeded it: one at 150 and one at 1,500 mg, about 19 times the screening level, according to the plan. The state’s 2013 health risk assessment projected that children’s blood lead levels would stay below 10 micrograms per deciliter. The Centers for Disease Control and Prevention has since lowered its benchmark for elevated blood lead in children to 3.5 micrograms per deciliter.
Regulators concluded the lead posed little risk because the high readings were isolated and the soil is now sealed. But health officials say no level of lead exposure in children is known to be safe, and the state’s risk assessment relied on a benchmark the CDC has since lowered.
Years of community advocacy
West Modesto residents and advocates point to other reasons their concerns have been largely brushed off over the years: who lives here, and how little time many of them have to fight back. In the unincorporated west Modesto community, about 71% of residents are Latino and a third were born outside the U.S., according to census data.
To the west, almond orchards and alfalfa fields stretch into Wood Colony, where some families still drink from private wells.
“The path of least resistance is always the communities that don’t have the time, resources, or information to push back,” said Matt Holmes, an adviser to Valley Improvement Projects. “There’s no more racist structure in the state of California than freeways, in my opinion.”
When officials held public meetings on the project, Wolfe said, “You had to know about the meeting to go to the meeting. … Most people don’t spend a lot of time on this. They’re busy raising kids, they’re going to work, they’re taking care of their families.”
After years of fighting for her community and her neighbors, Wolfe began to feel disillusioned and discouraged that her efforts might have been in vain. She would attend public meetings, with Stanislaus Council of Governments (StanCOG) or the Wood Colony Municipal Advisory Committee, and feel ignored and silenced every time she and her neighbors tried to bring their concerns.
“It always felt like they thought they knew better than we did,” Wolfe said.
Her frustrations are echoed by Teresa Gamboa, a Woodland West resident, who attended StanCOG meetings for eight years and went to Sacramento for answers.
“I never was satisfied,” she said. “Since the city and the county announced this project and said they wanted to build it, me and my neighbors didn’t want it.”
Coleman’s garden serves the same community. Families take the harvest home – squash blossoms for many Latino families and chard that some Assyrian neighbors roll into dolma. Recently, 60 third graders from Franklin Elementary cooked there with nutrition students from Modesto Junior College.
Despite concerns about contamination, she welcomes the bypass. She said truck traffic on Maze is nonstop all day long, especially big rigs.
Testing as the highway grows
StanCOG’s fact sheets promise the project will move trucks and commuters away from schools and churches on Maze Boulevard, ease congestion and cut emissions from idling.
Wolfe said the first segment mostly moved the traffic to other neighborhoods.
“It’s basically a commuter access to get in and out of Modesto,” she said. Because the road ends at Dakota Avenue, “it’s poured an enormous amount of traffic on the country roads in Wood Colony.”
Valley Improvement Project advocates say city planners now describe the corridor as a future industrial link between Highway 99 and Interstate 5, and not just a way to alleviate traffic along Maze. Holmes said the road should be redesigned to protect the neighborhoods it crosses.
“We shouldn’t be able to see the tailpipe, let alone breathe it,” he said
Valley Improvement Projects is doing its review under a DTSC technical assistance grant, the only one in the state where the state itself is the responsible party.
The group’s consultant, Hyphae Design Laboratory, will repeat the state’s sampling and test homes downwind of the old mounds, focusing on streets south of the bypass. Soil and well sampling is planned for January and February.
“We’re going into this project with a critical lens,” Telles said. If the state fell short, he said, the group may push to have the soil removed.
His VIP colleague Bruce said they’re open to whatever those results show: “I have my skeptical mind, but then I have to check it … we need to have an open mind about [how] they might have actually done it right.”
The state’s next formal checkpoint is a five-year review due in 2028. DTSC won’t certify the cleanup until a future phase widens the bypass to four lanes, a date its own records place in the early 2030s.
Coleman is building her community garden for longer than that. She is planting a 50-tree orchard in the future, and wonders if the toxic chemicals in the area will have an effect.
“I’m thinking, in 30 years will this still be here? Will we still be dealing with this?” she said.
StanCOG’s Lindsay Pangburn said the next segment of the Highway 132 bypass, from Dakota Avenue to Gates Road, does not touch the buried soil. Its 2022 environmental review identified up to seven homes and one business that could be displaced.
The segment reaches Lori Wolfe’s 18.2-acre ranch, where the state is seeking 3.3 acres through eminent domain for the expansion. Years after her family switched to bottled water after finding barium in their well water, she has watched the bypass move closer to completion while their questions about the toxic chemicals in her community went unanswered.
More answers may come at the end of this year, when Valley Improvement Projects begins testing soil and wells at homes near the old stockpiles. Wolfe isn’t sure what they’ll find, or whether she wants to know.
“The harder you look,” she said, “the more scary things look sometimes.”
Ximena Loeza is the bilingual communities reporter for The Modesto Focus, a project of the nonprofit Central Valley Journalism Collaborative. Contact her at ximena@themodestofocus.org.