Woodland Pulp Mill chemical release that killed two people deemed ‘preventable’, CSB says

BAILEYVILLE, Maine (WABI) - The U.S. Chemical Safety and Hazard Investigation Board (CSB) released an investigation update Tuesday on the January 27, 2026 toxic gas release at the Woodland Pulp mill in Baileyville, Maine — an incident that killed two employees and exposed 10 others to hydrogen sulfide gas.

Kasie Malcom, 20, and Allen Hornberger, 26, died as a result of the incident.

CSB Chairperson Steve Owens said the investigation is still ongoing, but “it already is clear that this terrible tragedy should never have happened.”

What investigators say happened

The CSB says hydrogen sulfide (H₂S) — an extremely toxic gas — was generated inside a process waste piping system known as the mill’s “acid sewer.” According to investigators, the gas ultimately escaped into the Kraft Mill building through holes and process openings in equipment.

Hydrogen sulfide is considered “immediately dangerous to life and health” at 100 parts per million (ppm). The CSB says the two employees who died were likely exposed to more than 500 ppm.

How the gas formed during shutdown operations

The CSB says the incident happened during a mill shutdown, when high‑pH (alkaline) process fluids containing sulfur compounds entered the acid sewer system.

A pH probe near the Wastewater Treatment Plant detected high pH and triggered an automatic increase of sulfuric acid to control pH. Investigators say liquids and chemicals built up at an “upward transition” in the pipe — slowing flow and delaying what the probe was “seeing.” The system continued calling for more acid, which reacted with sulfur compounds and created hydrogen sulfide gas.

Why the gas got into the building

The CSB says around 11:40 a.m., the Bleach Plant’s scrubber fan was turned off as part of shutdown operations. Without the fan creating vacuum to pull gases into the scrubber system, hydrogen sulfide built up and moved through connected piping and vessels — and then escaped into the Kraft Mill building.

Investigators say the gas leaked through multiple release points, including:

• A roughly 6-inch by 2-inch hole in a fiberglass gas collection pipe,
• Two 1-inch holes drilled for gas measurements years earlier that were never plugged, and
• An open drain pipe used to remove condensation.

The CSB describes that area as a hydrogen sulfide “release zone.”

Victims and exposures

The CSB says the two employees who died were on the second floor of the Kraft Mill, likely working on an equipment drawing project unrelated to the shutdown, about 15 to 20 feet from the release zone. Both collapsed.

Ten other workers in the building were also exposed. The CSB says some reported symptoms such as burning eyes, burning throat, and headaches. One employee on the first floor briefly lost consciousness but recovered after reaching fresh air.

Major safety gaps highlighted by CSB

In its update, the CSB says Woodland Pulp did not have several key protections in place, including:

• No system to control or account for personnel in the Kraft Mill building during the shutdown,
• No building ventilation system during normal operations or shutdowns, and
• No fixed hydrogen sulfide detectors or alarms — and the company did not provide or require personal hydrogen sulfide monitors.

Owens said the two employees were not found until hours after the release ended, leaving them exposed without assistance.

What happens next

The CSB says its investigation is ongoing and will continue reviewing:

• Hydrogen sulfide detection, alarms, and response
• Kraft Mill access control
• Process safety practices, including procedures, hazard controls, management of change, maintenance, and incident investigation.

The CSB is an independent, nonregulatory agency. It does not issue fines or citations, but can make safety recommendations to companies and regulators such as OSHA and the EPA.

View the preliminary report on the investigation here.

Berman & Simmons Attorney Elizabeth Kayatta represents the families of the deceased employees released the following statement:

“The Chemical Safety Board’s update is clear: neither Kasie nor Allen had anything to do with causing the toxic gas release,” said Kayatta.

“These two boys were casualties of a corporate culture that prioritized profits over people. Many questions still remain about the shocking disregard for safety that developed at Woodland Pulp while under the ownership of International Grand Investment Corporation.”

Woodland Pulp Mill representatives say they are aware of the CSB interim report and are reviewing it.

Due to other related investigations currently pending, they will not provide further comment at this time.