ANTIQUE – A toxicological analysis conducted by the Department of Health (DOH) has identified cypermethrin, a pesticide chemical, as the likely cause behind the mass fainting incident that hospitalized nearly 300 students in Barangay Pis-anan, Sibalom town on July 2.
The findings were based on an initial report by the DOH Toxicology Specialty Center at the Western Visayas Sanitarium and General Hospital in Iloilo and confirmed by Sibalom’s Mayor Gian Carlo Occeña in an official statement released on August 2.
“There was sufficient evidence of environmental contamination by cypermethrin within the school premises, most likely due to airborne pesticide drift compounded by weather conditions,” Occeña said.
Cypermethrin is a synthetic pyrethroid commonly used as an agricultural pesticide, particularly as a foliar spray on rice and other crops. In this case, traces of the chemical were detected on classroom walls, doors, and surrounding vegetation in Pis-anan National High School, strongly indicating airborne dispersal of the substance.
The incident caused widespread panic as students from both Pis-anan National High School and Pis-anan Central Elementary School complained of difficulty breathing, chest pain, vomiting, and chills after reportedly inhaling a foul odor described by many as similar to “rotten guava.”
According to the DOH toxicology report, these symptoms are consistent with acute exposure to pyrethroid pesticides, to which cypermethrin belongs.
In addition, urine samples from two students showed high levels of formic acid, pointing to possible methanol exposure — a substance commonly used as a solvent in some pesticide and fogging solutions.
Despite the findings, the mayor clarified that the report remains partial, with other environmental samples still undergoing laboratory analysis. These results are critical to fully establish the source and extent of the contamination.
“We are still awaiting the results of other environmental samples submitted for laboratory analysis, which are necessary to establish correlation with the toxicological results already obtained,” Occeña said.
The Sibalom local government continues to coordinate closely with health and environmental agencies as it seeks to ensure the safety of students and prevent similar incidents in the future./PN
