A fatal hydrogen sulfide exposure at Woodland Pulp’s Baileyville mill in Maine has prompted extensive safety changes at the facility and renewed discussion over personal gas monitoring across the US pulp and paper industry.

The January 27 incident exposed 12 employees to hydrogen sulfide (H₂S) in the mill’s bleach plant. Two workers — 20-year-old intern Kasie Malcolm and 26-year-old engineer Allen Hornberger — died following the exposure.

Six months later, federal investigations have provided a clearer account of the circumstances surrounding the incident, while Woodland Pulp has introduced personal gas detectors, fixed monitoring equipment, revised alarms and improved worker accountability procedures.

For pulp and paper mills handling hazardous process chemicals, the accident raises broader questions about gas detection, maintenance, shutdown procedures and knowing exactly who is inside potentially hazardous operating areas.

Hydrogen Sulfide Accumulated During Mill Shutdown

The incident occurred while Woodland Pulp employees were preparing to temporarily shut down the mill.

Hydrogen sulfide accumulated in a sewer line before escaping into the bleach plant, where workers could be exposed without immediately recognizing the danger.

H₂S is particularly hazardous because high concentrations can rapidly overwhelm workers. Although it can have a characteristic odor at lower concentrations, smell cannot be relied upon as a warning method because exposure can impair the ability to detect it.

Bleach plant operator Shawn Howland, who has worked at the facility for decades, said an electrician working nearby suddenly began running from the area after being affected by the gas.

Howland helped the worker outside before returning with other operators wearing respirators and carrying a handheld gas detector.

According to Howland, the H₂S concentration exceeded the measurement range of the instrument.

The operators escaped and recovered, but Malcolm and Hornberger were working on the second floor of the building and were not known by Howland to be inside at the time.

They subsequently encountered the gas.

Investigators Identify Multiple Safety Failures

Federal investigators have since examined the chain of events that allowed hydrogen sulfide to accumulate and enter the bleach plant.

According to findings cited from the US Chemical Safety Board (CSB), problems began months earlier following a failure involving the system used to monitor acidity in a sewer line connecting the bleach plant with the site’s wastewater treatment operations.

A backup arrangement was subsequently used.

The location of the acidity measurement was approximately 1,000 feet from the chemical addition point, according to Howland’s account. The resulting process conditions led to excessive chemical addition and a reaction that generated hydrogen sulfide.

At the same time, the mill was being shut down, and a scrubber fan that would normally assist with air handling had stopped operating.

Investigators also found that the gas was able to enter the bleach plant through openings, including holes that should have been plugged.

The combination demonstrates how several individual process and operational conditions can interact to create a much more serious industrial hazard.

Personal H₂S Monitors Become Central Issue

One of the most significant issues raised following the accident involves personal hydrogen sulfide monitors.

Howland said he had requested personal monitors from several superintendents during his 27 years working in the bleach plant but that the requests had been denied under different corporate ownership.

The small wearable devices continuously monitor the atmosphere around individual employees and provide an alarm when hazardous gas concentrations are detected.

The Chemical Safety Board noted that Woodland Pulp had not provided the personal monitors before the incident, while the Occupational Safety and Health Administration (OSHA) subsequently proposed four willful citations.

According to United Steelworkers representative Michael Higgins, appropriate personal monitors cost approximately $100 each.

Within days of the fatal incident, Woodland Pulp employees who required them were provided with the devices.

Fixed Gas Detection and Alarm Systems Added

Personal monitoring is only one of several changes introduced at the Baileyville mill.

Woodland Pulp has also installed fixed hydrogen sulfide detectors throughout the bleach plant.

According to Howland, activation of one of these detectors can now warn people throughout the four-story facility to evacuate while preventing other employees from unknowingly entering an affected area.

The mill’s alarm system has also been revised.

Another major change concerns worker accountability.

Investigators found that the company did not have an adequate system to account for everyone inside the bleach plant. Malcolm and Hornberger reportedly remained inside for approximately four hours before concerns were raised when they failed to meet a roommate as planned.

Howland said the mill is now working on an electronic system involving wearable wristbands or fobs that can help identify where personnel are located.

For large industrial facilities with multiple floors, maintenance activities and changing work crews, personnel tracking can become particularly important during emergencies.

Accident Carries Significant Human and Financial Costs

Beyond the deaths of two employees, the incident has resulted in substantial financial consequences.

The Chemical Safety Board estimated approximately $16 million in property damage and loss of use associated with the accident.

That figure is separate from approximately $800,000 in penalties proposed by OSHA and does not include potential costs arising from future legal action.

Woodland Pulp’s owner, International Grand Investment Corporation, declined to comment on the allegations concerning previous investment in maintenance and monitoring equipment while investigations remain underway.

Union Seeks Wider Requirements for Personal Monitoring

The consequences of the accident are now extending beyond Woodland Pulp.

Higgins plans to pursue state legislation that would require employers working with chemicals capable of producing immediately dangerous atmospheres to provide employees with personal monitoring equipment.

OSHA recorded 31 workplace deaths involving hydrogen sulfide between 2020 and 2024, with incidents occurring in sectors including wastewater treatment, oil and gas operations, hazardous waste handling and tanker cleaning.

The Woodland Pulp accident has also prompted discussion within the paper industry itself.

Howland presented the incident at a United Steelworkers health, safety and environment conference in Pittsburgh in May, sharing the circumstances of the accident with union representatives and paper industry managers.

According to Howland, a union survey at the conference suggested that personal gas monitoring is not universal across US paper mills.

Mill Safety Culture Under Scrutiny

The investigation has also brought attention to the relationship between maintenance investment and process safety.

Howland and Higgins have argued that insufficient resources for maintenance contributed to conditions preceding the accident. Woodland Pulp’s corporate owner has not commented on those allegations while investigations continue.

Since January, however, the mill has established a joint union-management safety committee, introduced additional monitoring systems and sent employees to safety training.

Howland described the changes as substantial, saying the bleach plant is no longer operating in the same way it did before January 27.

Lessons for the Wider Pulp and Paper Industry

The Woodland Pulp accident carries significance beyond a single Maine mill.

Pulp manufacturing involves chemical reactions, enclosed process systems, wastewater infrastructure and potentially hazardous gases. Effective protection therefore depends on multiple layers of control rather than a single piece of safety equipment.

Personal gas monitors, fixed detectors, ventilation, process instrumentation, preventive maintenance, alarm systems and reliable personnel accountability can each provide a separate layer of protection.

The incident also illustrates a difficult issue for mature industrial operations: a low frequency of previous accidents does not necessarily mean a hazard has disappeared.

Investigators examining the Woodland Pulp accident reportedly asked employees about a similar hydrogen sulfide incident at an Alabama paper mill roughly 25 years earlier in which two contractors died. Long-serving workers interviewed after the Maine accident did not remember it.

For pulp and paper producers, that may be one of the most important lessons from Baileyville. Maintaining process safety requires not only learning from accidents when they happen, but ensuring those lessons remain embedded in operating procedures, maintenance decisions and employee training years later.

Last Updated on 11/08/2026 by Jota Machinery