Test the Lennar site: There is no safe level for asbestos exposure

SF Bay Guardian Editorial, August 29, 2007

Test the Lennar site: There is no safe level for asbestos exposure
A committee of the San Francisco school board is discussing some sort of voluntary program to test for toxic exposure kids who attend facilities near Lennar Corp.’s construction project at Hunters Point. That’s set off a modest fury in the Department of Public Health, which insists there’s no threat to the public and no reason to test anyone. And the school district almost certainly doesn’t have the money to conduct a testing program for hundreds of students.

But the city should never have allowed this situation to develop to this point. And if there is real concern in the community (which there is) and any credible evidence that asbestos might be present in the air (which there is), then the Department of Public Health ought to do the only prudent thing and order a series of air and ground tests in the immediate vicinity of the Lennar site.

Lennar, as we’ve reported (see “The Corporation That Ate San Francisco,” 3/14/07), is running a massive Redevelopment Agency construction project on part of the old Hunters Point Shipyard. The construction stirs up a lot of dust, and there’s naturally occurring asbestos in the rock below. There may be other forms of toxic material in the dirt too, left by the military, which was never terribly good about keeping its bases clean.

The company was supposed to do air monitoring near the site; state law requires stringent tests whenever construction that could stir up asbestos takes place near an area where children congregate, and there are schools and rec centers right near the Lennar project. But the subcontractor handling the tests bungled them, so for 13 months there was no data on air quality at all.

The Muhammad University of Islam, a private school that adjoins the site, has been demanding better monitoring and asking for students to be relocated if the site isn’t safe. Some of the tactics of school representatives have been questionable: Department of Public Health workers going door to door in the neighborhood report that school supporters followed and intimidated them. And since there’s naturally occurring asbestos in rock, and the substance is used in products like car brakes, it’s entirely possible that there’s some presence of the deadly fibers in the air anyway, unrelated to anything Lennar may have done wrong. The Department of Public Health wants to avoid a needless panic.

But that doesn’t change the basic point: if there’s toxic dust in the air, and kids are being exposed, the public needs to know about it.

There is no safe level for asbestos exposure. The stuff can linger in the ground for years, and if it’s even slightly stirred up, it gets into the air, and breathing it is directly linked to fatal lung disease. It wouldn’t be that hard for a city team to take a few samples from the soil around the construction site; if the stuff is pretty thick on the ground, then kids clearly shouldn’t be playing there, and if the levels are even minor, then parents ought to be aware.

The supervisors failed on a 6–5 vote to approve a measure that would have called on Lennar to shut down construction, but they can certainly direct the Department of Public Health to conduct some basic safety tests — and make the results public.

Asbestos Fact Sheet
from the California Office of Environmental Health Hazard Assessment

Asbestos is the common name for a group of naturally occurring fibrous silicate minerals that can separate into thin but strong and durable fibers. The principal forms of asbestos include chrysotile, crocidolite, amosite, tremolite, actinolite, and anthophyllite. All but chrysotile are classified as amphiboles, which tend to have a thin, needle-like appearance. Chrysotile breaks into curly fibers. Asbestos deposits are located in many parts of California and are commonly associated with serpentine.

* Asbestos is classified as a known human carcinogen by State, Federal, and International agencies. Asbestos was identified as a Toxic Air Contaminant in 1986 by the Air Resources Board.

* Asbestos fibers can cause health problems if inhaled. When asbestos fibers become airborne, they can be inhaled deep into the lung. Many fibers deposited in the lung are retained there for long periods of time, others may be translocated to other parts of the body (e.g., the lining of the lung and abdomen), and others are completely cleared, albeit slowly. The fibers can cause chronic local inflammation and disrupt orderly cell division, both of which can facilitate the development of asbestosis and cancer. Thus, inhalation of asbestos fibers can initiate a chain of events resulting in cancer or other asbestos-related illness, which may not become apparent for years, even long after the exposure has ended.

* Most of the information on health effects comes from studies of workers exposed regularly to high levels of asbestos. In occupational settings all forms of asbestos have been shown to cause asbestosis, lung cancer and mesothelioma. Asbestosis is a noncancerous lung disease involving diffuse fibrotic scarring of the lungs. Persons with asbestosis can experience progressive shortness of breath. Lung cancer is associated with asbestos exposures; cigarette smoking and asbestos exposure multiply the risk of lung cancer beyond that caused by exposure to either of these materials separately. Mesothelioma is an incurable cancer of the lining of the chest cavity and abdomen.

* People have been exposed to asbestos by living with asbestos workers or living in the vicinity of asbestos mines and factories. People exposed to asbestos in such non-occupational settings have also had asbestos-related diseases including cancer. While most asbestos-associated cancers are related to the intensity and duration of exposure, reports in medical journals have linked some mesotheliomas to short exposure periods, on the order of months. Even in these cases, however, usually many years (20 years or more) elapse between the time of initial exposure to asbestos and the development of mesothelioma. In addition, there are reports of markedly elevated mesothelioma rates in populations living in areas in Greece, Turkey and New Caledonia with substantial quantities of tremolite in soil, particularly among individuals who used tremolite asbestos to whitewash their homes, resulting in substantial exposure. These populations had ongoing low-level as well as episodic high-level exposures to tremolite.

* There are some data that indicate amphibole forms of asbestos are more potent than chrysotile in inducing mesothelioma (but equipotent in inducing lung cancer). However, the data do not allow conclusive statements in this regard. Chrysotile and tremolite forms frequently occur together. Since many factors impact the potency of asbestos, the quantification of risk is inexact and at the present time all forms of asbestos are treated in risk assessment as equally potent carcinogens for both lung cancer and mesothelioma.

* Asbestos was used in many household and building products in the past. In part because of this indiscriminate dispersal of asbestos in the human environment in past years, it is common to find hundreds of thousands to millions of fibers in human lungs. Generally those with heavy exposures have greater asbestos lung burdens. For example, lung tissue taken from patients with mesothelioma often contains over a million fibers per gram of tissue.

* “Background” rates of mesothelioma for the general population in the United States with minimal exposure to asbestos are about 1 to 2 cases per 1 million people , though in communities in which there has been substantial occupational exposure such rates may be several-fold higher. Background rates for lung cancer are higher mostly due to smoking. Asbestosis is generally associated with occupational exposures but nonoccupational exposures, particularly to household contacts of people working in the industry, have resulted in asbestosis.

* For individuals living in areas of naturally occurring asbestos, there are many potential pathways for airborne exposure. Exposures to soil dust containing asbestos can occur under a variety of scenarios, including children playing in the dirt, dust raised from unpaved roads and driveways covered with crushed serpentine, uncontrolled quarry emissions, grading and construction associated with development of new housing, gardening and other human activities. For homes built on asbestos outcroppings, asbestos can be tracked into the home and can also enter as fibers suspended in outdoor air. Once such fibers are indoors, they can be resuspended by normal household activities, such as vacuuming (as many fibers will simply pass through vacuum cleaner bags).

The general public exposed to low levels of asbestos may be at elevated risk (e.g., above background rates) of lung cancer and mesothelioma. The risk is proportional to the cumulative inhaled dose (number of fibers), and also increases with the time since first  exposure. Although there are a number of factors that influence the disease-causing potency of any given asbestos, such as fiber length and width, fiber type, and fiber chemistry, all forms are carcinogens, and exposure should be minimized. The Air Resources Board has additional information on asbestos including ways to reduce exposure on its web page at  http://www.arb.ca.gov/toxics/Asbestos/general.htm

Thanks to Roland Sheppard at http://web.mac.com/rolandgarret for this.

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1 Response to “Test the Lennar site: There is no safe level for asbestos exposure”


  1. 1 Carol Cavanaugh May 9, 2011 at 1:36 pm

    This is terrible, asbestos should be banned! Check out http://www.banasbestos.us/ and http://www.weitzlux.com/asbestos_1962542.html


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