Efforts by the nation’s largest emitter of nitrous oxide to rein in the release of the potent greenhouse gas are behind schedule, allowing the emissions, which are relatively easy to eliminate, to continue to fuel climate change.

The chemical company Ascend Performance Materials produces adipic acid, a key ingredient in the manufacturing of nylon 6,6 and polyurethane, synthetic materials used in everything from carpeting to car parts and running shoes. The manufacturing process also produces as a by-product vast quantities of nitrous oxide, a climate super-pollutant. 

Ascend vented 27,528 tons of nitrous oxide into the atmosphere from its adipic acid plant near Pensacola, Florida in 2020, the most recent year for which data are available, according to figures the company reported to the EPA. Those emissions were equal to the annual greenhouse gas emissions of 1.6 million automobiles. That is more than five times the nitrous oxide emissions of any other U.S. plant.

On a per ton basis, nitrous oxide is nearly 300 times more damaging as a greenhouse gas than carbon dioxide, the primary driver of climate change. Nitrous oxide is also currently the most significant ozone-depleting substance released to the atmosphere following an international ban on more harmful ozone depleting substances. However, the gas, which is commonly used as an anesthetic by dentists, is generally considered to be not directly harmful to human health at low concentrations and is not regulated under the Clean Air Act.

Emissions of nitrous oxide from Ascend’s Pensacola plant, a sprawling chemical facility next to the Escambia River, place it among the nation’s top 25 greenhouse gas emitters alongside coal-fired power plants and oil refineries, the EPA data shows. Yet, unlike those other facilities’ carbon dioxide emissions, nitrous oxide pollution is easily abated through incineration or chemical decomposition. Other adipic acid plants in North America, Europe and Asia have been using low cost incinerators and chemical reactors to destroy 95 percent or more of their nitrous oxide since the 1990s.

Ascend destroyed or otherwise abated just 70 percent of its nitrous oxide emissions in 2020 and the sheer scale of the plant’s operations—it is the largest adipic acid production facility in the world—mean these remaining emissions have an outsized impact.

Company officials told Inside Climate News in early 2020 that they would voluntarily reduce their remaining nitrous oxide emissions by 50 percent by mid-2020 and should achieve a “well over 95 percent” emissions reduction by February of 2022. But instead of decreasing, nitrous oxide emissions from Ascend’s Pensacola plant increased by 50 percent in 2020, EPA data show. Air permits filed with state regulators in Florida do not indicate that the company is moving forward with more ambitious reductions of the potent greenhouse gas.

“When you look under the hood, we have a lot of questions about whether those steps are really being taken,” said Jessye Waxman, campaign strategist for Climate Strategies Lab, a newly launched environmental advocacy organization focused on reducing greenhouse gas emissions from heavy industry, of Ascend’s emission reduction efforts. “We know that the technology is there and it’s definitely possible to abate at 95-plus percent. Ascend is not there. So, as we’re looking at the chemicals industry, as we’re looking at major manufacturers in the United States, Ascend certainly stands out as a sore thumb.”

Company officials said the company is moving forward with emission reduction efforts.

“We have completed the first phase of our investments to reduce N2O by 50 percent [of remaining emissions] and we are currently working on the second phase of the project to create reductions in excess of 90 percent [of total emissions],” Chris Johnson, Ascend’s director of sustainability, said in a written statement. “We expect this phase to be completed by the end of this year.”

Ascend has been working to develop its own nitrous oxide recycling technology since 2015. Ascend’s destruction of N2O is voluntary, however the rate at which it has abated nitrous oxide has decreased significantly in recent years, from a high of 91 percent of total emissions in 2015 to just 70 percent in 2020 according to EPA data.  

Johnson did not specify when the 50 percent reduction in emissions was completed, however a sustainability report published by Ascend last year said the first phase of a new nitrous oxide emissions reduction project was brought online in late 2020. Johnson did not say why the emission reduction efforts were delayed, however the global pandemic and related supply chain issues may have played a role. 

The company sold carbon offsets from nitrous oxide emissions reductions in 2021 through the Climate Action Reserve, a non-profit organization that facilitates carbon trading. The Reserve shows that Ascend sold emission reduction credits equal to nearly 1.3 million metric tons of carbon dioxide in the first half of 2021.

If the company continued selling offsets at the same rate in the second half of 2021, the carbon offsets would equal a 35 percent reduction in nitrous oxide emissions based on the company’s 2020 emissions, a significant improvement but still shy of the company’s 50 percent reduction target.  

The only other adipic acid plant in the country is a plant in Victoria, Texas owned by chemical manufacturer Invista. Invista abates approximately 97 percent of its nitrous oxide emissions and, unlike Ascend, it is not eligible to sell carbon offsets for its existing emissions reductions. Invista’s predecessor, DuPont, added the pollution controls at the plant voluntarily in 1997. State regulators now require Invista to abate approximately 95 percent of the nitrous oxide it produces.

How quickly and to what extent Ascend reduces its nitrous oxide emissions could affect its financial outlook because SK Capital, Ascend’s owner, has been reported to be considering selling the company. Bloomberg reported in December that SK Capital, a private equity firm, was considering an initial public offering of the company. However, Barry Siadat, a co-founder of SK Capital and chairman of Ascend Performance Materials, said the article, which cited unnamed sources, was a “baseless rumor.”

If SK Capital does proceed with an IPO, Ascend’s outsized emissions may give investors pause.

“If I was looking at this company and the track record on not only setting targets, but managing its overall GHG emissions, they do seem like they’re late to the game,” Lauren Compere, managing director of Boston Common Asset Management, an investment firm that focuses on environmental issues, said, referring to greenhouse gas emissions.

“Their record is poor relative to their peers in leveraging the use of existing, low-cost abatement technology,” she said. “It calls into question, I think, the company’s overall management of sustainability and understanding what expectations are out there, from both investors and customers.”

In the 1990s, the cost of nitrous oxide abatement technology averaged around $10 million per plant, according to a peer-reviewed study published in 2000. Adjusting for inflation, the cost would be approximately double that amount today. The novel chemical recycling approach Ascend is pursuing would add additional cost, though the expense would likely be relatively modest for the company, the value of which Bloomberg placed at $5 billion.  

“In the grand scheme of things, it’s a relatively small operating cost,” Waxman said.   

Meanwhile, Invista is working with the China Pingmei Shenma Group, one of the largest manufacturers of adipic acid in China, to voluntarily destroy Shenma’s nitrous oxide emissions.

Invista will license its nitrous oxide abatement technology to Shenma as part of a larger agreement, in which Shenma will provide Invista with adipic acid for nylon 6,6 production. The agreement could result in a reduction of nitrous oxide emissions by as much as 14 million tons of carbon dioxide equivalent per year, according to a Jan. 18 press release from Invista. That is the greenhouse gas equivalent of the emissions from 3 million automobiles per year.

However, questions about the agreement remain. Invista previously installed pollution controls at Shenma’s adipic acid production facilities in the early 2000s through a United Nations program that provided incentives for Shenma and other Chinese producers to abate their nitrous oxide emissions. It’s unclear if the agreement with Invista includes new or expanded pollution controls or simply provides the chemical catalysts required to run existing equipment.

Shenma previously told Inside Climate News that it continued to abate its emissions after funding for the U.N. program dried up in 2012. However, company officials declined to say what percent of their emissions are destroyed or captured for reuse. Shenma did not respond to a request for additional information. Invista declined to comment.

Waxman said she is “guardedly optimistic” that the agreement is a sign that Chinese manufacturers are beginning to shift to stronger pollution controls. China produces nearly half of the world’s adipic acid and many of the country’s 11 production plants may not be abating the vast majority of their nitrous oxide.

What is driving Shenma and Invista, a subsidiary of Koch Industries, may have less to do with environmental concerns and more to do with financial sustainability, because brands that use nylon 6,6 and polyurethane are beginning to look further up their supply chains when assessing the climate impact of their products, she said.   

“Moving away from suppliers that have outsized greenhouse gas footprints in comparison to peers is a really easy move,” Waxman said.

She added, “They really need to step up their game on sustainability, and the easiest way that they can do this right now, and have a big impact on slashing their emissions, is using that nitrous oxide abatement technology.”