WTC Radon Alarm Puts Rebuilding in Limbo Again

I think someone's trying to hush this up. Yesterday, there was an article in the Post, with a title along the lines of "Oh, No! Ew, Another Problem: Radon in Land under WTC" or something. Now it's gone.

Below the relevant article from the Times.

"WTC Radon Alarm Puts Rebuilding in Limbo Again"

By ADAM P. RUSH and INEZ LANSKY
Published: March 31, 2010

At the World Trade Center construction site, rumors abound that the rebuilding project in the wake of the devastating terrorist attacks might be derailed by an invisible, colorless, odorless, tasteless, but radioactive terror: radon-229 gas. Radon is a known carcinogen and the second most frequent cause of lung cancer, after cigarette smoking, causing 21,000 lung cancer deaths per year in the United States.

Radon occurs naturally as the decay product of radium. If traces of radium are present in underground rock, radon gas from these natural sources can accumulate in buildings, especially in confined areas such as attics and basements.

The primary route of exposure to radon and its progeny is inhalation. Radiation exposure from radon is indirect: The health hazard from radon does not come primarily from radon itself, but rather from the radioactive products formed in the decay of radon.

If radon gas is inhaled, the particles that result from its radioactive decay may attach to the inner lining of the lung. These radioactive particles remain lodged in the lungs and continue to decay further, causing continued exposure by emitting alpha radiation.

Of the 35 known isotopes of radon, radon-229 may very well be the sneakiest, as it evades all standard chemical tests for radon. It can only be detected by mass spectrometers and very sensitive Geiger counters. Due to its stealthy characteristics, the isotope is nicknamed "radoff" by scientists.

The problem is compounded by the fact that radon-229 is much more dangerous than the more common radon-222, particularly for smokers. While prolonged exposure to radon-222 roughly doubles a nonsmoker's risk of contracting lung cancer, radoff is twice again as harmful for nonsmokers. For regular smokers, long-term exposure to high concentrations of radoff can boost their cancer risk to almost 100%. The products from the decay of radoff lodge in the lungs more easily and are particularly destructive to the already damaged lungs of smokers.

In the absence of other causes of death, the absolute risks of lung cancer by age 75 at usual radon-222 concentrations of 0, 100, and 400 Bq/m3 would be about 0.4%, 0.5%, and 0.7%, respectively, for lifelong nonsmokers and about 25 times greater (10%, 12%, and 16%) for cigarette smokers. The corresponding numbers for radoff are about 0.9%, 1.3%, and 1.9% for lifelong nonsmokers and 60%, 72%, and 96% for cigarette smokers.

Due to its hard-to-detect and hazardous nature, if found, the presence of radoff requires complex and extensive mitigation measures, like ground insulation of basements and custom HVAC systems. In most cases, demolition and new construction is the cheapest alternative.

While radon itself is rare in Manhattan, radoff is even rarer. Although it is more commonly encountered in cities in or near mining districts, like Pittsburgh or Denver, and major earthquake zones, like Los Angeles, it is not unheard of in New York, where it can emanate from pockets in the Manhattan schist.

The building 18 West 11th Street had to be demolished due to radoff contamination. Radoff was also found in the basement of the American Radiator Building during its conversion into The Bryant Park Hotel, whose boarded-up state is still remembered by many New Yorkers. Demolishing the building and starting the hotel from scratch would have been much cheaper than the conservationist approach known as adaptive-protective radoff in-location mitigation, but as the building had already been landmarked, the former was never an option.

The rumors regarding radon and radoff at the WTC site could neither be corroborated nor refuted. Neither the Port Authority of New York and New Jersey, which owns the land under the WTC, nor Larry A. Silverstein, the developer, nor the New York City Department of Health and Mental Hygiene returned calls.

The engineer and developer, Alan F. Termarch, a partner at One Astor Plaza Realty Investors, LLC, and at Rad-on/Rad-off, the only radoff mitigation contractor in the city, wasn't surprised by this radio silence. "Developers and even public officials are extremely reluctant to come forward with a finding of radoff, as that's too often the death sentence for a project," he said. "Just like inhaling radoff is a virtual death sentence for a smoker."

Mr. Termarch estimates the extent of the necessary mitigation work at billions of dollars and several years in delays. "Obviously, the cheapest way to keep radoff out of a building is pouring several seamless layers of concrete and plastic under the building. Obviously, you can't do that if the building's already in place. Can't undermine all of its columns at the same time, right? Might be cheaper to rip out everything built at the WTC site in the past eight years and start over."

A version of this article appeared in print on April 1, 2010, on page A22 of the New York edition.