NRG and the Sussex County Cancer Cluster

I attended yesterday's meeting of the Environment Committee of the Delaware Cancer Consortium to learn more about the cancer cluster identified in the six zip codes surrounding NRG's Indian River power plant. I didn't stick around for the announcement of an agreement for eventual implementation of emission controls at the plant. The News Journal has the story:

The handshake agreement between NRG and the Department of Natural Resources and Environmental Control would allow NRG to miss deadlines for limiting emissions of nitrogen oxide and sulfur dioxide by 2009. But it would require NRG to surpass state requirements before 2012, when more stringent rules go into effect.
The agreement also states NRG will meet caps on mercury emissions by 2009, and improve on more stringent rules by 2012, one year ahead of schedule.

Even though the agreement allows NRG to put off implementing controls to meet the state's new, stricter standards, state officials seemed pleased:

Lt. Gov. John C. Carney Jr. said the agreement "sounds like a very positive thing to me" because the company will spend time limiting emissions instead of fighting in court.

Environmental activists aren't so pleased:

But Citizens for Clean Power said in a statement its members were concerned NRG was getting "a pass" to cut pollutants that cause respiratory conditions like asthma and possibly lung cancer.
"We request that DNREC explain to the public why NRG is incapable of meeting the regulations as written," the group wrote.

For my part, I can't help but wondering whether NRG set aside plans to put new controls in place while it pushed its proposed coal gasification plant as the way to meet new standards. This is pure speculation on my part; I'd be happy to learn more and be proven wrong.
The session included presentations on the statistics of the cancer cluster. Identifying the cause or causes of a cancer cluster is difficult. It's hard to establish a clear causal connection between a source of pollution and the onset of cancer in a population. It's much easier for instance to establish a causal connection between inhaling cigarette smoke and lung cancer, which is why it is possible to state with a high degree of certainty that most lung cancer is caused by tobacco use.
Which is why the committee decided that the next step in studying the cancer cluster is to try to isolate tobacco use as the possible primary cause of the elevated incidence of lung cancer.
Ali Mirzakhalili, who manages DNREC's Air Quality Management Section, offered an interesting presentation on the atmospheric pathways of the small particles referred to as PM2.5 (particulate matter with a diameter of 2.5 micrometers or less). PM2.5 has been identified as a significant cause of asthma, bronchitis and other chronic respiratory ailments.
Using air sampling data and detailed wind patterns from the National Oceanographic & Atmospheric Administration (NOAA), he made a plausible case that the majority of PM2.5 particles in Delaware's air come from neighboring states and as far away as the Ohio Valley. Mirzakhalili described Delaware as sitting in the middle of a "transport crossroads" where pollutants from hundreds of miles away converge.
I was pleased to finally meet some downstate environmental activists, Kim Furtado and Kit Zak (having met Bill Zak last week). These dedicated and knowledgeable activists have played a significant role in turning Delaware in the direction of wind power and away from burning more coal in Delaware.