LOUISIANA (From news reports) -- A Bogalusa paper mill known for chronic odor problems has accepted a $500,000 fine from federal regulators over alleged monitoring breakdowns and elevated air releases of sulfur compounds that can produce a rotten egg smell.

International Paper, the owner of the mill, also agreed to operational and inspection changes, employee training and recordkeeping improvements and potentially upgrades of a key incineration furnace that was the focus of regulators' concerns, according to the U.S. Environmental Protection Agency settlement.

Known as a "consent agreement and final order," the deal caps nearly four years of consultation between EPA and International Paper over alleged U.S. Clean Air Act and state environmental violations from the paper mill dating from 2017 and 2018.

International Paper, which did not respond to requests for comment, is a publicly traded worldwide company with a market value of nearly $28 billion and net earnings of $557 million in 2024, despite flat sales in its North American industrial packaging business.

Under the deal, signed Feb. 20, the company did not admit to the violations alleged in the settlement nor in earlier notices of violation that led to the agreement.

In operation for more than a century, the pulp mill and related corrugated box plant are a mainstay of Washington Parish's lumber industry and was the parish's third-largest employer in 2024, with 650 workers, according to parish School Board audit figures.

The mill recently survived a round of closures by International Paper that will shutter the Red River containerboard mill in Campti by April, according to state economic officials.

Environmental groups, however, have criticized the EPA for not doing enough to control all hazardous emissions from the mill and others like it. The Bogalusa pulp mill also operates, in part, under older and now replaced federal hazardous air rules that allow the plant to exclude air exceedances due to startups, shutdowns and malfunctions.

Rotten egg smells have been a source of regular complaints to state regulators, agency records show.

The Bogalusa mill uses the kraft chemical recovery process to make pulp from wood and manufacture paper products. It also uses a chemical from the wood, known as lignin, to help power its operations in addition to natural gas.

However, the mixture of chemicals used to break down the wood is well known to produce a smell, what one paper from a forestry trade research association calls "kraft odor." The sulfur-based chemicals typically released are hydrogen sulfide, methyl mercaptan, dimethyl sulfide and dimethyl disulfide.

EPA notices of violation dating from 2021 and 2023 that led to the settlement zeroed in on a series of emissions exceedances of those sulfur-based hazardous air pollutants, but also alleged a failure to report a gap in the monitoring of nitrogen oxides when continuous monitors were down for 187 hours.

The final settlement only dealt with alleged violations related to emissions of "total reduced sulfur," monitoring rules for that category of sulfur-based chemicals, and measures to prevent unrecorded air releases and leaks.

Nitrogen oxides contribute to particulate pollution and ground-level ozone that can enter the blood stream and, with long-term exposure, can worsen respiratory conditions, like asthma, and cardiovascular problems, according to the EPA.

Hydrogen sulfide and other sulfur compounds can cause headaches, vertigo, fatigue and neurological problems with long-term exposure, according to the EPA.

In two instances cited in the settlement, for example, the mill exceeded the air standard for total reduced sulfur on Aug. 14, 2017, and again on Sept. 27, 2017, on average over 12-hour periods those days. State regulators sometimes just missed catching them.

On the August 2017 date, TRS emissions were 75% higher than the 12-hour standard, the settlement alleges, citing the company's own reporting to regulators.

The day before the alleged sulfur emissions exceedances on the afternoon of Sept. 27, 2017, a member of the public complained to the EPA, saying that "'you can really see and smell the smoke (coming from the mill)," according to state a Department of Environmental Quality report.

A state inspector first showed up the next day, on Sept. 28, 2017, and made subsequent visits and inspections through mid-October but only detected a mild odor during visits in early October. A records check found no emissions exceedances or process upsets on Sept. 26, 2017, and the 10 days beforehand, the DEQ report says.

A few weeks later, in a required quarterly submission, International Paper ended up reporting to DEQ and EPA exceedances of sulfur emissions on Sept. 27, 2017.

In two other cases, in February and May of 2018, International Paper was accused of failing to report exceedances of sulfur emissions to regulators. EPA inspectors later found them in backup data from the plant's required continuous monitoring system for sulfur, the settlement alleges.

In another alleged violation, International Paper left six bypass valves without a seal or other way to know whether they had been opened and were releasing hazardous air emissions.

Since International Paper bought the paper mill from Temple-Inland in 2012, the company has spent close to $490 million on upgrades.

International Paper is planning another upgrade to replace equipment that ties into a furnace that was the main source of alleged emissions violations in the EPA settlement in hopes of improving operational efficiency, according to a proposed state air permit.

The upgrades are expected to lead to newer federal air rules applying to the plant that further limit exclusions for air exceedances, though in other cases older rules will remain in effect, permit records say.