The Navy will vent Tank 20 at the Red Hill Bulk Fuel Storage Facility this week. This is the eighth tank to enter the degassing phase as part of the process toward permanent closure. Workers will continue to defuel, ventilate, and clean the tanks, with air-quality checks in place while they are inside.
With a green light from the Hawaiʻi Department of Health, Navy Closure Task Force‑Red Hill says it will begin safe, deliberate ventilation — or degassing — of Tank 20 ahead of interior cleaning and pipeline work, according to Navy Closure Task Force‑Red Hill. Tank 20 is the eighth of 14 tanks slated for ventilation under the current plan, and six of the facility’s 20 tanks were already empty and out of service before the defueling push began. The move is billed as a measured step toward decommissioning the site perched above Oʻahu’s main aquifer.
Regulators set stop‑work thresholds and public notice rules
The Hawaiʻi Department of Health’s conditional approval lays out near‑real‑time air monitoring, public notice at least 12 hours before venting begins and clear stop‑work triggers if exposure levels climb. Under DOH’s rules, active ventilation must stop if the one‑hour time‑weighted average of total VOCs at the exhaust stack tops 20 parts per million by volume, and venting must cease — with public and DOH notification — if any perimeter monitor hits an acute exposure limit of 38 parts per million by volume. The department also capped how many tanks can be vented per year and how many can be vented simultaneously to dial down risk, per the Hawaiʻi Department of Health.
Monitoring network and early readings
NCTF‑RH has installed nine air‑quality monitoring stations around the Red Hill perimeter — including one at the Halawa Correctional Facility — to track total VOC levels and local weather, with hourly updates pushed to a mobile app and daily AQM summaries posted during venting periods. The Navy’s AQM page details how to find the near‑real‑time data and monitor locations, giving regulators and the public a clear view as the work proceeds. Since degassing began in summer 2024, readings have stayed well below state thresholds, averaging about 0.045 ppmv total VOCs, as reported by Maui Now and the task force’s monitoring documentation.
Where this step fits in the closure timeline
Venting Tank 20 follows a months‑long defueling mission that removed more than 100 million gallons from the underground tanks and a formal transfer of authority for final closure work to the Department of the Navy. Briefings indicate the effort has shifted from defueling into the slower grind of cleaning, pipeline removal and environmental remediation, with closure plan supplements submitted to state and federal regulators as work continues, as mentioned by the Department of War and the U.S. Navy. Officials say full closure includes tank cleaning and sludge removal, dismantling more than 10 miles of pipeline and long‑term environmental work around the site.
How neighbors can follow the work
Residents and nearby institutions can track hourly AQM readings and venting notices via the task force’s public dashboards and its mobile app; community groups and the Navy have urged folks to enable push alerts for real‑time updates. The app launch and instructions on finding hourly AQM readings were outlined in NCTF‑RH outreach and a DVIDS news post about the mobile app and dashboards, per DVIDS and Navy updates.
