[link|http://www.latimes.com/news/science/environment/la-na-toxic29mar29,0,2725321,full.story?coll=la-home-headlines|LA Times]:

TCE is the most widespread water contaminant in the nation. Huge swaths of California, New York, Texas and Florida, among other states, lie over TCE plumes. The solvent has spread under much of the San Gabriel and San Fernando valleys, as well as the shuttered El Toro Marine Corps base in Orange County.

Developed by chemists in the late 19th century, TCE was widely used to degrease metal parts and then dumped into nearby disposal pits at industrial plants and military bases, where it seeped into aquifers.

The public is exposed to TCE in several ways, including drinking or showering in contaminated water and breathing air in homes where TCE vapors have intruded from the soil. Limiting such exposures, even at current federal regulatory levels, requires elaborate treatment facilities that cost billions of dollars annually. In addition, some cities, notably Los Angeles, have high ambient levels of TCE in the air.

An internal Air Force report issued in 2003 warned that the Pentagon alone has 1,400 sites contaminated with TCE.

Among those, at least 46 have involved large-scale contamination or significant exposure to humans at military bases, according to a list compiled by the Natural Resources New Service, an environmental group based in Washington.

The Air Force was convinced that the EPA would toughen its allowable limit of TCE in drinking water of 5 parts per billion by at least fivefold. The service was already spending $5 billion a year to clean up TCE at its bases and tougher standards would drive that up by another $1.5 billion, according to an Air Force document. Some outside experts said that estimate was probably low.

[...]

The military has virtually eliminated its use of TCE, purchasing only 11 gallons last year, said Beehler, an attorney who used to head environmental affairs for Koch Industries Inc., a large industrial conglomerate in Wichita, Kan.

[...]

Spending $5B (at least - that's only what the AF will spend) to clean it up, and only buying 11 gallons (in the whole of DoD) in 2005 is quite a bit different from The Guardian's comment:

The Pentagon stalled efforts to clean water supplies contaminated by a carcinogenic chemical despite evidence that it posed a significant health risk to millions of people, it was reported yesterday.

The Environmental Protection Agency (EPA) investigated the solvent, trichloroethylene, extensively used on military bases, after significant quantities were found in water supplies.

The LA Times story is pretty balanced, IMO.

The Guardian makes it sound like the DoD wasn't doing anything other than fighting the EPA and continuing to use TCE. It's much more complicated than that. Painting the DoD as the Evil Military and the EPA as the Selfless, Principled Public Servants doesn't help anyone really understand the situation.

The 2003 Air Force report is [link|http://www.afcee.brooks.af.mil/at/restorationsummit/2003/Att_G_TCE_Atlanta_REO_TCE.ppt|here] (1.4 MB .ppt). The military doesn't dispute that TCE is a dangerous chemical and that it needs to be cleaned up. But they don't agree that reducing the groundwater standard Maximum Contamination Level from 5 micrograms/liter (5 ppb) to 1 microgram/liter (1 ppb) (or lower) will reduce health risks:

Phase I:
Based on the RMIS database search

*There are more than 1,400 DoD sites with TCE contamination in soil and/or groundwater (Approximately 700 Air Force sites)
*Most sites with TCE-contaminated groundwater have concentrations greater than the current MCL
*Most remedial actions are expected to be groundwater extraction and treatment
*It will cost DoD more than $5 billion to clean up to the current MCL
*Change would result in substantial cost increases without reducing risk

A grain of salt is about [link|http://www.physlink.com/Education/AskExperts/ae342.cfm|60 micrograms]. So 5 ppb is about 1/10th of a grain of salt per 32 oz of water. It's a pretty tiny amount. I can't say whether 5 ppb of TCE is dangerous while 1 ppb is safe. I don't know.

But let's look at this [link|http://www.dhs.ca.gov/ps/ddwem/chemicals/PHGs/TCEMCLreport12-01.pdf|California Department of Health Services] report (13 page .pdf):

Cancer is the primary health concern from TCE exposure. Depending on the particular exposure scenario, animal study, and tumor site selected in the PHG risk analysis, the range of drinking water concentrations within the de minimis level (10^-6; one excess cancer case in one million people exposed over a lifetime of 70 years) ranges from 0.1 to 64 ppb. Since the 5 ppb MCL is within that range, it meets the acceptable risk level of 10^-4 to 10^-6 that Federal and State regulatory agencies use for establishing drinking water MCLs to protect public health.

DHS adopted the MCL of 5 ppb in 1989, based on the OEHHA risk assessment stating that it fell within the range of de minimis risk levels. The US EPA adopted the same MCL as DHS in 1991. Although the updated OEHHA risk assessment has not significantly changed from the initial assessment (the PHG of 0.8 ppb falls within the de minimis range), since the PHG is almost an order of magnitude lower than the MCL and TCE is still detected in some drinking water supplies, DHS has conducted a comprehensive review.

Emphasis added.

As I read it, the range is a factor of 640 (0.1 to 64). That's huge and both ends are in the estimated de minimis risk level. In other words, going from 5 ppb to 1 ppb is an insignificant change in the risk - it's in the noise of the estimate.

Based on what I've been able to find in the last hour or so, it seems to me that it's not cut and dried that spending billions more on reducing the TCE concentration in groundwater below 5 ppb is the best use for the money to reduce the health risk from TCE.

And to be honest, it's not clear to me that every potential health hazard should be reduced to a 1 in a million risk of cancer, either. For example, the death rate (over a lifetime) from cancer is about [link|http://www.physics.isu.edu/radinf/risk.htm|20%]:

One is that in the US, the current death rate from cancer is approximately 20 percent, so out of any group of 10,000 United States citizens, about 2,000 of them will die of cancer. Second, that contracting cancer is a random process, where given a set population, we can estimate that about 20 percent will die from cancer, but we cannot say which individuals will die. Finally, that a conservative estimate of risk from low doses of radiation is thought to be one in which the risk is linear with dose. That is, that the risk increases with a subsequent increase in dose. Most scientists believe that this is a conservative model of the risk.

So, now the risk estimates. If you were to take a large population, such as 10,000 people and expose them to one rem (to their whole body), you would expect approximately eight additional deaths (0.08%*10,000*1 rem). So, instead of the 2,000 people expected to die from cancer naturally, you would now have 2,008. This small increase in the expected number of deaths would not be seen in this group, due to natural fluctuations in the rate of cancer.

What needs to be remembered it is not known that 8 people will die, but that there is a risk of 8 additional deaths in a group of 10,000 people if they would all receive one rem instantaneously.

So, say, in a city of 1 M people, instead of 200,000 people dying of cancer over their lifetime, 200,001 would die of cancer if TCE was in the water at the 10^-6 level rather than 200,010 at the 10^-5 level. I hope I'm not the only one who thinks that spending $10M or more to bring about that improvement may not be the best use of the money.

My $0.02.

Cheers,
Scott.

:-)

As I said, I don't know whether making the standard more stringent will help or not. If it were clear that all cancers were caused by environmental exposures of some sort, and if there were no other use for the hypothetical $10M that would be spent at that site, then the choice would be clear: The DoD, NASA, and DoE should quit their bellyaching and spend whatever it takes to clean all of it up. Unfortunately, it's not at all clear that that's the case.

Too often in discussion of these issues, the risks and costs are taken in isolation. I don't think that makes much sense. Yes, "cost/benefit analysis" can be distorted by those with axes to grind, but it needs to be an important part of the process of deciding what we should do to improve health (and prosperity as well).

[link|http://www.meds.com/lung/seer.html#quest_19|This] link gives the probabilities of dying of various common cancers:

19. What are the probabilities of dying of the most common causes of cancer death in men and women? (based on 1989-1991 mortality rates)

Men . . . . . . . . . . . . . . . . . . . . .Women

Site . . .Probability (%) . . Site . . . . . Probability (%)

All races

All sites . .. . . 23.35 . . . . All sites . . . . 20.39
Lung and Bronchus . 7.09 . . .Lung and Bronchus . . 4.09
Prostate . . . . . .3.41 . . . . Breast . . . . . . 3.59
Colon and Rectum . .2.60 . . Colon and Rectum . . . 2.65
Pancreas . . . . . .1.08 . . . .Pancreas . . . . . .1.18
Stomach . . . . . . 0.86 . . . . Ovary . . . . . . .1.07

Just about everyone agrees that most lung cancers are caused by smoking, radon, or environmental exposures (dust). Surely DoD facilities have areas where people are exposed to lung hazards that could be better addressed by increased funding and attention.

[link|http://www.atsdr.cdc.gov/tfacts19.html|TCE facts]:

Some studies with mice and rats have suggested that high levels of trichloroethylene may cause liver, kidney, or lung cancer. Some studies of people exposed over long periods to high levels of trichloroethylene in drinking water or in workplace air have found evidence of increased cancer. Although, there are some concerns about the studies of people who were exposed to trichloroethylene, some of the effects found in people were similar to effects in animals.

In its 9th Report on Carcinogens, the National Toxicology Program (NTP) determined that trichloroethylene is \ufffdreasonably anticipated to be a human carcinogen.\ufffd The International Agency for Research on Cancer (IARC) has determined that trichloroethylene is \ufffdprobably carcinogenic to humans.\ufffd

Emphasis added.

TCE is bad and needs to be cleaned up to reasonable levels. Reasonable is the operative word, IMO, and people of good faith can argue about what that reasonable level is. Despite the Guardian's take, it's not at all clear, IMO, that taking the MCL to 1 ppb or less will make a difference in people's health, while there's little doubt that decreasing people's workplace exposure to fine dust and radon will be beneficial.

I hope it's a little clearer where I'm coming from.

Cheers,
Scott.
(Who is reminded of [link|http://www.sourcewatch.org/index.php?title=Alar_and_apples|Alar] - yes there's a risk. But how big is it?)

It was also used as a herbicide.

[link|http://72.14.203.104/search?q=cache:WnvJuPi-5WAJ:hq.environmental.usace.army.mil/Corps_Environment/story12.html&hl=en&gl=us&ct=clnk&cd=2&client=firefox-a|Google Cache]:

During the 1950s and 1960s, the U.S. Department of Defense was responsible for the protection of the East Coast from communist missile invasion and the execution of an offensive missile attack. The highly specialized radar systems were susceptible to oxidation, corrosion and electrical shorts due to oils used on the equipment. Chlorinated solvents performed an excellent job in cleaning the electronics. In particular, trichloroethylene (TCE) performed a superior job in this cleaning effort and it didn\ufffdt take very much to clean the equipment. Unfortunately, today it doesn\ufffdt take much TCE to contaminate groundwater to a level that is unsafe to drink.
\t
In addition, the toxicity value of TCE was found to be so effective that it was occasionally used as a defoliant to eradicate unwanted weeds or woody vegetation at the DoD facilities. The government did nothing wrong, for it followed standard waste disposal practices when using TCE, but society didn\ufffdt understand health implications of contaminants in our drinking water at that time.

Now 40-50 years later, we are trying to recover the TCE discharged at these facilities via sub-surface septic systems, waste disposal sites, floor drains and/or stormwater collection systems. Complicating this effort is the fact that these facilities were constructed on the highest topographic features to gain the most direct and unobstructed radio and radar signals. The geology of these locations in New England is typically fractured metamorphic and igneous rock. This rock is typically referred to as "hard rock" and it is generally a solid media with small fractures or fissures making up the porosity. This geology makes our job of determining groundwater and contaminant flow very difficult. Two Defense Environmental Restoratin Program Formerly Used Defense Sites, Glenburn and Bucks Harbor, Maine, demonstrate geophysical techniques to determine groundwater and contaminant flow. Both projects have TCE contaminatino in the bedrock aquifer.

[...]

Cheers,
Scott.