Rescue teams are searching for survivors after a portion of the Rizal Provincial Sanitary Landfill collapsed Friday afternoon, with an urban poor advocacy group claiming as many as 50 people remain missing.

The Rodriguez police confirmed that at least three people were officially reported missing following the 20 February incident at the facility in Barangay San Isidro.

However, the group Kadamay reported that based on accounts from residents at the site, approximately 50 people are unaccounted for and nearly 100 residents have been affected.

“We do not have formal data yet,” Kadamay secretary-general Mimi Doringo said. “The estimate of 50 is based on the number of families we spoke with who are still waiting for updates on their loved ones.”

Two young siblings were rescued after being submerged in the garbage for over an hour. Doringo said one child was buried up to the waist while the other was buried up to the neck before bystanders pulled them to safety.

The landfill is operated by the private firm International Solid Waste Integrated Management Specialist Inc. (ISWIMS).

Meantime, local authorities, including the Rodriguez Municipal Disaster Risk Reduction and Management Office, have declined to provide a formal statement, deferring comments to the private operator.

ISWIMS offices were closed on Sunday, and a guard at the facility stated no staff were available for comment on weekends.

Advocacy group Protect Rizal suggested that quarry blasting in the vicinity may have triggered the collapse.

This is not the first fatal incident at the site. In 2013, a similar “trash avalanche” at the same landfill buried four workers alive. The facility also faced a temporary closure in 2008 for discharging toxic leachate into the Montalban River.

Rights groups are calling for a transparent investigation and are urging the local government to ensure the safety and legal protection of the estimated 1,000 families whose livelihoods depend on the landfill.