State Urged Use of "Innocuous Gases" to Avoid Emissions Risk

By Walter F. Roche Jr.

In a Sept. 2 letter to US Nitrogen a Tennessee environmental official encouraged the company to use harmless gases to test whether repair efforts on the $200 million facility had been successful.
"To the extent practicable, we encourage US Nitrogen to test the efficacy of repairs with innocuous gases prior to introducing process gas on a production basis," Michelle W. Owenby wrote in the letter to US Nitrogen Plant Manager Andrew W. Velo.
Use of nonlethal gases would reduce or eliminate the risk of any harmful gases being released to the atmosphere.
The encouragement apparently came too late as US Nitrogen already had begun restarting its nitric acid production plant using the normal process, according to a letter Velo had sent to the state Department of Environment and Conservation the very same day.
Owenby, director of TDEC's division of air pollution control, offered the encouragement in a two-page letter in which she asked Velo to provide a detailed report on the incidents of Aug. 23, which produced an orange cloud of nitric oxide and nitrous dioxide that loomed over the 500 acre US Nitrogen site.
Owenby also asked for the results of US Nitrogen's own investigation of the incident and remedial actions taken to prevent a recurrence.
"Please provide information regarding any startup attempts subsequent to Aug. 23 and the result of those attempts," the letter continued, adding that the information was being requested as part of TDEC's ongoing investigation of the Aug. 23 incident.
She said that investigation would also be looking at "any other excess emissions that have occurred as part of the startup of the nitric acid plant."
TDEC also has asked the Greene County company to provide copies of any startup, shutdown and malfunction logs associated with the nitric acid plant from April 29, 2016 to the present."
As reported previously Velo wrote to Owenby, also on Sept. 2, to report that the equipment malfunction. a sticking valve, had been pinpointed as the cause of the excess emissions and production resumed on Aug. 31.
"The startup went well, as the plant started up correctly with the pressure in the plant as expected," Velo wrote.
He did note however, that an attempted startup on Aug. 29 had to be aborted after less than 20 minutes "because an additional issue with an instrument was identified."
In his letter Velo also has asked TDEC for an extension in deadlines for performing tests and providing emissions data over a 30 day period of continuous operation of the nitric acid plant.
Due to startup delays Velo wrote that it would be impossible for the company to meet the existing deadlines.
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