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Ash Deposition Event (9/18/09)

The Department of Environment and Conservation responded immediately to the ash deposition incident on September 18, 2009, and has investigated the cause of deposition. This was related to a process problem at the TVA Kingston plant, and not the ongoing cleanup of the spilled ash at the site. At the open house meeting held on October 1, TDEC announced that it had directed TVA to conduct a root cause analysis of the cause of the deposition incident and that it would be ready on October 10, 2009. TDEC received the executive summary on October 9. Click here to view the summary. TDEC received the full report from TVA on October 20 and has formally reviewed the document. To view the full report, click here.

Click here for the November 9, 2009 TDEC response to TVA's root cause analysis of September 18, 2009 ash deposition event.

The department has collected a sample of the material deposited in the community and sent it to the lab for analysis. While there wasn’t enough material available to collect for chemical analysis, physical analysis of the material indicates it consists mostly of fly ash.

TVA has been required to significantly reduce the nitrogen oxide and sulfur dioxide emissions from its Kingston plant to improve air quality in the Greater Knoxville Area and to improve visibility in the Great Smoky Mountains National Park.

Often times, the coupling of selective catalytic reduction units that remove oxides of nitrogen and scrubbers that remove sulfur dioxide can create a new pollutant when the two technologies are coupled together. TVA will begin sustained operation of the first of its two scrubbers at Kingston soon. TVA needed to determine what adjustments were needed to prevent the formation of sulfur trioxide and the plume observed may have been a result of the testing, but there are other possible explanations including a start up due to oil firing of another unit separate from the units being tested with different types of coal. The coal testing is one of the scenarios the department is reviewing, though we are still working to determine the precise cause. Again, the root cause analysis will assist us in making a final determination and that is forthcoming soon.

As part of the process of bringing the air new pollution control equipment online, TVA made a request to the state Air Pollution Control Board for a temporary variance from their opacity standards (visible emissions from the stack) to do experiments with varying types of coal in anticipation of the start-up of their new scrubbers.The experiments involve fine-tuning other pieces of air pollution control equipment so as to prevent increased visible emissions after the startup of the scrubbers occurs.

The state Air Pollution Control Board approved the variance with TDEC’s recommendation, though it’s important to note that variance does not give TVA permission to drop material onto the surrounding area. Similar approvals and experiments occurred at the TVA Cumberland and Bull Run steam plants without incident and we had no reason to believe this situation would be different, though we are committed to getting to the bottom of it.

TVA has suspended test burns and surrendered the variance in opacity standards issued by the Air Pollution Control Board. TDEC is also reviewing procedures to provide additional notification to communities through their public officials when variances are scheduled before the Air Pollution Control Board.

The Department of Environment and Conservation is committed to seeing this investigation through, and sharing the results with the community.