Despite an announcement that it had achieved full production capability in early 2017, US Nitrogen faced pressure from local citizens and regulators after a nitric acid vapor release in April and other issues.

In response, the company is taking part in an alert system with other Midway-area manufacturing facilities and added an audible siren system meant to warn residents within a 2-mile radius of the plant should there be another emergency.

US Nitrogen produces liquid ammonium nitrate, a component for blasting agents produced by parent company Austin Powder.


A little after 6 p.m. on April 19, 2017, a broken gasket at US Nitrogen’s Pottertown Road facility released about 424 pounds of nitric acid vapors into the air, according to an October Tennessee Department of Environment and Conservation report.

The release elicited a response from several local and state emergency agencies, including sheriff’s deputies who went knocking on doors of nearby residents to warn them to shelter in place and turn off air conditioner units in their homes.

The gas eventually dissipated, and TDEC and US Nitrogen officials said they found no evidence of any injuries from the incident, though at least one person has said she has suffered eye problems after the release.

TDEC issued a report in October saying TDEC would not be penalized for the release due to technicalities in federal law but also because not enough nitric acid was emitted to warrant a penalty. TDEC regulators don’t believe the environment or human safety were affected by the release, they wrote.

Still, the incident triggered talks that eventually led to Greene County beginning its own countywide alert system for emergency notification, to which US Nitrogen contributed funds. Midway-area industries pooled resources to begin an alert system to alert each other of similar incidents in the future. And US Nitrogen eventually paid for and erected two sirens on its property to warn the public within a 2-mile radius of such an event.

Those sirens were deemed operational in early 2018.


A state inspection report released in November 2017 highlighted a number of deficiencies at US Nitrogen, many of them involving record keeping matters, and officials at the chemical plant have vowed to submit a plan of action to the state next year on how they plan to correct the issues.

The Tennessee Department of Environment and Conservation compiled a 17-page compliance inspection report and notice of violation. The inspection, a routine one checking for compliance with current permits, was done on-site by TDEC and the Environmental Protection Agency between Oct. 17 and Nov. 15 of this year.

Many of the items had to do with reports and record keeping.

US Nitrogen had incorrect calculations for monthly water discharge reports. Robbie Helton, US Nitrogen Safety and Administrative Services manager, said in late 2017 the deficiency was not related to the plant’s discharge performance or incorrect analytical results.

“It is simply an administrative difference in how analytical results are averaged for monthly reporting,” he said.

Helton said the administrative discrepancies, such as the proper way to mark out incorrect entries in logbooks, were already being addressed.

The report also cited an “operational mishap” in early 2017 that resulted in the mixing of steam and condensate with ammonium nitrate solution. The affected water was contained on site in a lined pond system and US Nitrogen flushed and refilled the system and worked to eliminate the ammonia and nitrate solution.

It was contained on-site until it could meet the permitted discharge parameters, Helton said. The TDEC report noted that TDEC should be notified when such mishaps happen.

There were also some water and sanitary sewage releases to unpaved areas on the site. TDEC said in the report that releases to unpaved areas meet the definition of releases to the environment. The report said regardless of quantity, a spill to the environment is required to be reported.

TDEC officials say the chemical plant should report those types of situations to the state. But Helton contended the plant did not violate their permits.

Other noted items included a water flow meter not being verified, laboratory logbooks not being reviewed often enough, some incorrect documents, improper documentation or a lack of documentation.

Maintenance of barriers preventing pollution was needed as well as the stabilization of a pile of soil.

“US Nitrogen documents and reports all routine and non-routine plant activities per our requirements under our permits, and state and federal regulations,” Helton said. “We have, in fact, gone well above and beyond the communication requirements in our interactions with our regulatory agencies.”

US Nitrogen responded to the report in early 2018, with officials saying they didn’t consider many of the issues cited in the report as permit violations.

“US Nitrogen does not believe that most of the ‘deficiencies’ mentioned in the report constitute violations of any statues, regulations or permits,” Plant Manager Andy Velo said in the response. “Additionally, the report consistently fails to identify the specific applicable statutory, regulatory or permit requirements that were allegedly violated.

“Finally, US Nitrogen notes that the report does not identify any noncompliance which could cause a threat to public drinking supplies, or any other discharge which could constitute a threat to human health or the environment.”

TDEC issued a response, affirming its position, and giving US Nitrogen longer to produce action plans to deal with the deficiencies it noted.


During back-and-forth communications with TDEC, Velo also communicated in March 2017 that “market conditions, equipment limitations and safety considerations” led to production slow-downs in early 2017.

Velo said in the letter that “the market for our product has changed such that we are able to produce more nitric acid and more ammonium nitrate than we can sell.

“These market conditions are certainly beyond our control, and we certainly did not anticipate them.”

According to a company statement issued in March, in calendar year 2017 US Nitrogen shipped a total of 68,642 tons of finished liquid ammonium nitrate for parent company Austin Powder.

“US Nitrogen has taken every opportunity to grow and improve its operations during the startup phases of the facility both internally and in concert with our community,” the company statement said. “Our internal philosophy requires that we take the proper steps in identifying improvement opportunities and apply those to our processes and procedures. It is our goal to operate our plants in a safe and compliant manner that meets all regulatory requirements.”

US Nitrogen officials also pointed out what they said were signs of their partnership with the Greene County community, including:

• contributing a majority of the funding and building materials for a fire training center to be located in Greeneville, which is scheduled to be completed in mid-2018;

• a “significant” financial contribution to the countywide Greene County 911 emergency alert system; and

• the development of the industrial alert system as well as the audible siren warning system.