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December 21, 2014

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Asbestos proves to be a microscopic road block near Boulder City

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L.E. Baskow

UNLV geology professor Brenda Buck and associate professor Rodney Metcalf confer over samples in their lab. They found asbestos in Boulder City that is delaying construction of a highway bypass.

In November 2011, two UNLV scientists touched carbon tape to a sample of bluish-grey mineral on the face of a rock found south of Henderson, then placed it under a microscope. The computer screen showed telltale white fibers, long and slim, like miniature straws.

The dirtiest asbestos cleanup sites

Asbestos is a mineral fiber found in rock and soil. In the ’60s and ’70s, it was a popular building material.

• Eldorado Hills, Calif.: Naturally occurring asbestos was found in this Sacramento suburb in September 2003 in the soil of the high school. In less than a year, after about $2.5 million in cleanup costs, the EPA and Oak Ridge High significantly cut the health risk to students by landscaping to reduce dust and prevent asbestos fibers from getting airborne.

• Clear Creek Management Area, Calif.: Atop one of the largest asbestos deposits in the world, this recreation area sits on a 29,000-acre serpentine deposit in San Benito and Fresno counties. Inside is the Atlas Asbestos Mine Superfund site, which first got the EPA’s attention in 1984 when large amounts of erosion caused asbestos to flow downstream into the California aqueduct. Since then, the water has been cleaned up, all the mines closed and measures taken to stop erosion. The Bureau of Land Management designated the area as hazardous and propped asbestos warning signs up at entrance points.

• Libby Superfund Site, Mont.: Libby, a former mining town of fewer than 3,000, has been on the EPA’s National Priorities List of most contaminated sites since 1983. In June 2009, it was designated a public health emergency. Contamination was town-wide, partly because residents used vermiculite as a soil additive in their gardens.

• North Ridge Estates Superfund Site, Ore.: Also on the National Priorities List, North Ridge Estates is a residential subdivision near Klamath Falls. Asbestos remnants were found across 50 acres of the neighborhood. The source: demolition debris from the Marine Recuperational Barracks, a complex of about 80 1940s-era buildings that housed soldiers recovering from tropical illnesses. In 2005, exposure risk was determined to be so high that residents were temporarily relocated for the summer when children were on school break and the climate was driest and windiest.

• Torch Lake Superfund, Mich.: From 1868 to 1968, copper mining and smelting operations dumped an estimated 200 million pounds of toxic tailings containing asbestos into Torch Lake on the east side of Lake Michigan. The primary concern is the ecosystem, particularly bottom-dwelling animals whose volume was, pre-cleanup, 20 percent contaminant.

• Carter Carburetor, Mo.: Carter Carburetor, a gasoline and diesel engine manufacturing plant just outside of St. Louis, was active from the 1920s to about 1984, when it was dismantled. Asbestos, found in machinery, furniture and building parts, along with toxic polychlorinated biphenyls and trichloroethylene used in the manufacturing process, were found at unacceptable levels.

It was what they feared: asbestos.

Asbestos used to be modern society’s friend — its strong, flexible, heat-resistant fibers mined and spun into insulation, fireproofing and decorative ceiling finishes. Only later was it discovered that, in certain forms, it can cause respiratory problems including scarred and inflamed lungs and, in extreme cases, cancer.

When UNLV geoscientists Brenda Buck, Rodney Metcalf and their colleagues published a scientific paper eight months ago on the presence of naturally occurring asbestos in Clark County, the effects were immediate and potentially far-reaching.

The discovery has stalled plans, more than 10 years in the making, to build a $490 million highway detour around Boulder City so traffic can move smoothly between Las Vegas and Arizona. Until that new highway is built, tourists, truckers and commuters must use Highway 93, which slices into town and slows miserably on busy days.

Beyond that, the first evidence of naturally occurring asbestos in Clark County may conceivably affect development not yet imagined. Asbestos becomes dangerous when disturbed, when it can be inhaled. That means construction potentially could whirl up a deadly cloud. Because the asbestos is a part of the landscape, cleanup is tough.

Bypass delays have frustrated the town.

“We can’t handle the traffic,” Boulder City Mayor Roger Tobler said. “If there’s an accident, it shuts down the whole town. I think this community is tired of what’s going on, and they have been for 10 years.”

The Nevada Department of Transportation and Regional Transportation Commission, partners in the bypass project, are frustrated too, with their own questions: Where exactly is the asbestos-carrying rock? Will construction activity stir it into the air? What is the health risk to workers and travelers?

Construction was scheduled to begin this spring but was put on hold in April to allow for asbestos testing and analysis. Results are expected next month.

NDOT, which is leading Phase I of the project — a 2.5-mile connector heading east from Highway 95 — is prepared to begin construction as soon as it gets the green light. The RTC’s work — a 12.5-mile stretch that finishes the bypass to near the Colorado River — isn’t scheduled to begin until early 2015.

But construction plans may have to be adjusted to reduce workers’ exposure to dust, and bids still need to be sought for contractors.

“Everyone wants to make sure that we proceed in the right manner, and I think we’re doing that,” Tobler said. “I don’t think (the asbestos) is going to hurt the project like it has in other places. I think we’ll be able to move forward.”

But asbestos has a history of slowing major public work projects. In Ambler, Alaska, its presence in a gravel pit stalled an airport expansion and sewage lagoon project for more than a decade. Outside San Jose, Calif., it delayed a $718 million dam replacement for at least three years, and workers now are required to wear protective clothing and decontaminate before leaving the site.

There are no federal regulations for dealing with naturally occurring asbestos. It’s left to states to create regulations based on Environmental Protection Agency and Occupational Safety and Health Administration guidelines addressing dust control, monitoring of air and soil, and worker exposure.

Nevada hasn’t created such regulations. Native asbestos doesn’t fall under county air quality standards, and Nevada OSHA has yet to address worker protection. For the most part, everyone is waiting for the test results or for the problem to come knocking on their door. Even the EPA, though aware of the Boulder City asbestos and acting as an adviser for mitigation, is waiting for a request from local officials before getting directly involved.

Meanwhile, Buck and Metcalf continue the research that sparked the issue.

Buck, who specializes in medical geology, started the asbestos study in 2011. A sample from the McCullough Range in Clark County, just south of Henderson, showed mineral actinolite — one of the six regulated forms of asbestos.

They teamed with scientists from the University of Hawaii, home to leading researchers on medical asbestos exposure, and started writing proposals for additional research funding, which they received in spring 2013. The mineral trail led them from the rolling, rocky hills of the McCullough Range overlooking Lake Mead to Highway 93 at Eldorado Dry Lake, a popular site for off-roading and Fourth of July parties, to the heart of Boulder City, beside Martha P. King Elementary School, and the outskirts of its southern and eastern neighborhoods. Every sample contained the fibrous amphiboles.

What was particularly concerning was that the type of asbestos fibers the geologists discovered are known to be particularly dangerous, and their breadth was much more extensive than what the UNLV team originally had thought.

“As soon as we found this out, we worked as fast as we could and as hard as we could to get the data published so that we could inform the public,” Buck said.

The fibers were similar to those found in Libby, Mont., where asbestos-rich mineral vermiculite was mined, leading to the town’s designation 15 years ago as a Superfund site. Many Libby residents have been diagnosed with asbestos-related illnesses, including cancer, due in part to their churning vermiculite into their gardens and vegetable patches as a soil conditioner.

The size and shape of the fibers, along with the type of mineral, determine how toxic it is. If it’s small enough, it becomes respirable. Of the fibers Buck and Metcalf found, 97 percent were respirable.

Dormant, undisturbed asbestos isn’t typically a problem. It’s often left in buildings and insulation because it isn’t dangerous unless it becomes airborne. In fact, the act of removing it often presents more danger than leaving it alone.

But that won’t be possible in construction of the highway bypass because explosives are needed to cut a route through the hills.

Thus the challenge: How to ensure the health of construction workers and motorists?

Part of the task includes assessing how extensive the asbestos is. To that end, the geologists are training the transportation departments’ asbestos analysts to spot the kind of rock that hosts the fibers.

There is no known amount of safe exposure to asbestos. But Michele Carbone, a leading researcher of mesothelioma, the cancer linked with asbestos exposure, said the immediate health risks are minimal. Risk rises with the amount of exposure and the concentration of fibers. Signs of the disease may not be evident for 40 years or more.

“Obviously, there is a significant risk, but the odds are you won’t get cancer,” Carbone said. “It takes significant, prolonged exposure. It’s not like shaking hands with someone, and you get the disease. People shouldn’t panic.”

Carbone, of the University of Hawaii, is working with Metcalf and Buck to test their samples on animal and human cells. His colleague Francine Baumann, an epidemiologist specializing in asbestos exposure, is looking at rates of mesothelioma and other asbestos-related illnesses in Southern Nevada to determine if the population already is at risk. She’s looking for trends of disease in young people and women, people least likely to be affected from working in places where asbestos might be present.

Nevada is not a hot spot for the disease; as of 2009, mesothelioma struck only about 20 Nevadans a year, keeping pace with the national average.

“Until we know more, one solution is to try and reduce exposure,” Buck said.

Off-road enthusiasts, for instance, may be encouraged to ride somewhere other than the Eldorado Valley.

Today, Buck and Metcalf are mapping the area where the asbestos may lurk, looking into areas with similar geology such as Searchlight, Laughlin and Lake Mead. And they’re trying to get funding to collect air samples, to determine the risk of exposure from different activities, including four-wheeling, horseback riding or simply taking a walk in areas that contain the asbestos.

When they go into the field, they’re careful, wearing respiratory devices and protective clothing. They take their own cars instead of the UNLV geoscience department’s vehicles, so they don’t expose students. They’ve notified UNLV geology, biology and anthropology departments to close down contaminated zones to fieldwork.

They’re worried about their own exposure, having spent years in the field kicking up dust and hammering into contaminated rock. They’re hoping it’s not as bad as it could be.

But they won’t know the answers until their research is complete.

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