How Much Asbestos Is Too Much?Lots of fibers, for years and years.
Posted Thursday, July 19, 2007, at 7:15 PM ETNo asbestos was found in the air after Wednesday's steam pipe explosion by New York's Grand Central Station, though debris and dust in the area did contain the carcinogenic mineral. City officials said that brief exposures are "very unlikely" to cause long-term health problems. Just how much asbestos does it take to make you sick?
PRINT
DISCUSS
E-MAIL
RSS
RECOMMEND...
Facebook
MySpace
Mixx
Digg
Reddit
del.icio.us
Furl
Ma.gnolia
Sphere
StumbleUponUsually, it takes years of continued exposure to high levels of asbestos—like those in an industrial environment—to cause health problems. People working under those conditions are more likely to develop lung cancer, mesothelioma, asbestosis, or abnormalities in the lining of their lungs. (According to an EPA review of asbestos data, factory workers exposed for a year to a significant dose of 44 asbestos fibers per cubic centimeter of air had their rates of lung cancer go up by 2.8 percent.) Scientists have plenty of data on these severe cases but much less information about what happens when you inhale small amounts of asbestos—e.g., at rates of less than one fiber per cc of air. At low levels of exposure, the effects may depend on the type of asbestos fiber inhaled, as well as the genetic makeup of the victim and whether he or she is a smoker.
But anecdotal evidence shows that very low levels of exposure can make you sick decades down the road. In Libby, Mont., a town whose largest employer for 70 years was a vermiculite mine, the CDC found rates of asbestosis in the population that were 40 to 60 times higher than expected. Since these illnesses take so long to crop up in general, it's hard to gauge original levels of exposure. Researchers believe that in some cases, the victims had exposure below what current OSHA standards allow in the workplace.
According to federal rules, employers must make sure there's less than 0.1 asbestos fiber per cubic centimeter of air averaged over an eight-hour workday. Workers can be subjected to levels of one fiber per cubic centimeter over periods of half an hour. (In industries like plastics manufacturing, which involves asbestos, the limits are pushed up to half a fiber per cc over the course of a workday, or 2.5 fibers for half an hour.) For any commuters caught in Wednesday's blast, though, the health risk was essentially zero.
Got a question about today's news? Ask the Explainer.
Explainer thanks Vikas Kapil of the Centers for Disease Control and Prevention, Aubrey Miller of the U.S. Environmental Protection Agency, and William Rom of NYU Medical Center and Bellevue Hospital.
The Tiger-Obama Cover Golf Digest Wishes It Could Unprint
Khalid Sheikh Mohammed's Trial Will Be Fair Enough
AOL's Plan To Flood the Web With Idiotic Celebrity Content
Amazing Photos of Obama's Secret Service Agents at Work
If You Want To Fix Darfur, Fix Chad First
A Close Reading of the Victoria's Secret Christmas Catalog
Remarks from the Fray:
Asbestosis and asbestos-related lung cancer are dose responsive diseases, which means that only people who inhale a lot of asbestos are likely to get these diseases. Mesothelioma, which is the more severe and less common disease associated with asbestos is not dose responsive. Some unfortunate individuals (In law school, we learned about "eggshell skull" plaintiffs, people who are profoundly affected by something that would not affect the average person) can get mesothelioma from very low levels of asbestos exposure. For example, I represented a plaintiff who got mesothelioma from only a few years of working on a machine that had asbestos brake linings in the 1980's. It was not thought necessary to remove the brake linings from the machine because the risk of becoming sick from such exposure was so low. My mother knew a man whose wife had died of mesothelioma -- her father brought asbestos dust home from work on his clothes when she was little, and her mother had also died of the disease. But her father, who worked with asbestos all his life, did not get sick. Classic "eggshell skull" cases.
However, these types of cases are few and far between. The average person who is exposed to a tiny amount of asbestos will not get sick from it (and certainly, people who work in buildings where asbestos is contained within the walls and not flying around are at no risk). Even the average client of mine, retired asbestos workers who had installed asbestos insulation for their entire careers, only got asbestosis, a disease which affects breathing and may be a precurser to mesothelioma, assuming the person does not die of something else, which they usually do, as it takes many years for the person to become sick.
Asbestos was a terrible product for those who installed it, and seeing the documents where the companies who marketed it knew the risk to those workers and continued to sell the stuff is a great argument for 1) never trusting corporate America when they say a product is safe and 2) never voting for a political candidate who favors tort reform and damages caps, because fear of lawsuits is the only thing that keeps stuff like this from happening again. But, that said, the amounts of asbestos that are around now do not pose a serious risk to most people. You are probably at a greater risk from mold in your building.
--Acidtongue
(To reply, click here.)
The asbestos that invades your lungs is most dangerous when it has separated into microscopic fibers. Those fibers can be inhaled into the tiny airways, deep in the lung, that are analogous to and adjoining the capillaries in the lung. The wall that separates the tiny airways from the tiny blood vessels is the wall cross which oxygen gets into the blood and carbon dioxide comes out of the blood. (Remember osmosis?)
The fibers that are inhaled are so small they cannot be seen with the naked eye. They are measured in microns. If one were to look at these fibers under a microscope they would appear as flat specs of material; however, the thin edges are not straight planes. They look like razor blades with the teeth of a saw.
Once asbestos fibers are inhaled they remain in the lung forever, embedded in the lung tissue. They do not deteriorate. It is also very difficult to determine that they are there, because of their size and their embedded location. Diagnosis is generally made based upon the long range symptoms.
If that were all that there is to it, the asbestos would have a kind of congestive impact, but it gets worse. The lung consists of elastic tissue, which enables breathing by inflation and deflation of the lung.
Well, every time one breaths, those little saws move and make microscopic cuts in the lung. The person does not feel that occurring. Every place there is a microscopic cut, there soon develops a small bit of scar tissue. Each bit of asbestos fiber cuts over and over and over again. Over the years, a lot of scar tissue can develop. Scar tissue is NOT elastic. As more of the lung develops scar tissue, the lung becomes less and less elastic. The lung can no longer fulfill its function adequately. Breathing becomes labored and that is not reversible.
So, if one walks through a cloud of microscopic asbestos fibers (or worse, runs through it or pauses to gasp for air), one can be in deep, long range, non-remediable trouble.
Let's take a different scenario. One lives or works in a building where microscopic fibers flake off from the places where asbestos is installed. That may be because of a draft or because of someone brushing up against it or building vibration or because of deterioration of a wrapper from around the asbestos. Those fibers go into the air and you breath them in over a course of time, perhaps over the entire time you are living or working ior studying in that place.
Large quantities of inhaled asbestos can injure quickly. Small quantities can accomplish the same injury over time.
--HJBoitel
(To reply, click here.)
(7/21)