Silliman University Statement on the Spent Wash Spill at the Tañon Strait Protected Seascape
Silliman University (SU) expresses its deep concern and solidarity with the communities and ecosystems affected by the catastrophic spill of untreated molasses wastewater into the Tañon Strait Protected Seascape (TSPS), the Philippines’ largest marine protected area, encompassing more than 500,000 hectares between Negros and Cebu.
On the night of October 26, 2025, the wastewater lagoon of Universal Robina Corporation’s (URC) Bais Distillery collapsed, releasing large volumes of molasses-based ethanol wastewater (spent wash, vinasse, or stillage) into Bais Bay. This incident has caused severe water discoloration, fish kills, and algal blooms, gravely threatening the ecological integrity and biodiversity of the Tañon Strait.
In immediate response, SU mobilized scientific teams to assess the environmental impacts in coordination with government agencies and local partners. On November 1, 2025, a team from SU, in coordination with the Department of Environment and Natural Resources–Tañon Strait Protected Seascape (DENR-TSPS) and URC representatives, conducted a preliminary water quality assessment confirming oxygen depletion in the affected waters. The following day, November 2, 2025, another SU team, together with DENR-TSPS, URC, the Philippine Coast Guard (PCG), and the Manjuyod Bantay Dagat, carried out a rapid field assessment to determine the extent of the spill and severity of fish kills.
Preliminary results from on-site surveys and drone-based Geographic Information System (GIS) mapping indicate that the spent wash plume has affected between 4,494 and 6,000 hectares of marine and coastal waters as of October 31 and November 2, 2025, according to data from both SU and DENR-TSPS. Localized fish kills were observed up to seven kilometers from the spill source. Interviews with fish pen and corral operators in Manjuyod revealed economic losses ranging from approximately PhP 1,000 to PhP 1.8 million per operator, along with extensive damage to seaweed farms during the peak of the fish kills on October 27, 2025. These findings provide a scientific basis for guiding immediate response measures and supporting evidence-based rehabilitation and management strategies.
SU stands in solidarity with the affected communities and remains steadfast in its commitment to science-based environmental action, accountability, and ecological restoration. The University continues to support the Department of Environment and Natural Resources -Negros Island – Siquijor Region (DENR-NIR) through ongoing water quality and biological assessments, technical advisories, and the formulation of rehabilitation plans. These efforts address both immediate mitigation and long-term recovery, including habitat restoration, fisheries management, and livelihood revitalization.
SU strongly recommends the urgent repair of the collapsed lagoon and containment structures, the implementation of transparent and regular water quality monitoring, and strengthened multi-sectoral coordination to prevent further ecological damage. The University also highlights the need for strict compliance with environmental safety and pollution control standards to protect marine and coastal ecosystems.
Finally, SU calls for full accountability and comprehensive restoration from all responsible parties to uphold environmental justice for the affected communities and ecosystems of the Tañon Strait. The University urges collective vigilance, shared responsibility, and sustained stewardship of our common marine heritage so that the Tañon Strait Protected Seascape and the life it sustains may continue to thrive for generations to come.
