The incident occurred on Wednesday, October 21, 2026, with affected students receiving treatment at the State Hospital in Ijebu-Ode, the General Hospital in Ijebu-Igbo and other healthcare facilities.
Among the worst-hit schools were Ijebu-Igbo Girls Grammar School, Anglican Girls Grammar School in Ijebu-Ode and Itamerin Comprehensive High School in Ago-Iwoye.
Videos circulating on social media showed some students reportedly fainting and being rushed to hospitals after inhaling the substance.
A teacher at one of the affected schools said the incident began at about 10 a.m., when students and staff started experiencing breathing difficulties.
“The students and staff started inhaling the gas and began having difficulty breathing. Some fainted and were subsequently rushed to hospitals,” the teacher said.
The teacher added that some schools in Ago-Iwoye were forced to close around 11 a.m. as the situation worsened.
“Some parents who heard about the unfortunate incident also came to pick up their children because nobody knows what is happening. We even heard that this gas leak has been occurring since April, sending hundreds of students to hospitals whenever it appears unexpectedly,” the teacher said.
Expressing concern over the recurring incidents, the teacher called on the government to expedite investigations and identify the source of the emissions.
The latest occurrence marks the fourth reported incident of its kind in Ogun State this year.
In April, about 40 students were reportedly affected by a similar incident. In May, more than 120 students were said to have been hospitalised following another exposure, while at least 69 students were hospitalised on June 1 after a further occurrence.
Following the June incident, the state government identified the gas as methane.
Governor Dapo Abiodun had said the government was collaborating with the Ministries of Environment and Health, the Nigerian Midstream and Downstream Petroleum Regulatory Authority, and the Department of Geology at Olabisi Onabanjo University to determine the cause of the emissions.
“Twice now, we have recorded cases of pollution in this school and some neighbouring schools. What is interesting is that the gas pollution occurred at about the same time in the affected schools—about three schools altogether—and this happened on two separate occasions,” the governor said at the time.
He explained that gas analysers had been installed in the affected schools following the initial incident to determine the nature and concentration of the substance.
“Following the first occurrence, we installed gas analysers across the schools to determine the nature and concentration of the gas, which has now been confirmed to be methane,” Abiodun stated.
The governor added that preliminary findings suggested possible geological factors, including fault lines beneath the affected locations, could be responsible for the emissions. He said the government was awaiting the final report from experts investigating the matter.
Reacting to Wednesday’s latest incident, the state Commissioner for Environment, Ola Oresanya, said, “We are on top of the situation.”
According to Daily Trust, the General Manager of the Ogun State Environmental Agency, Kehinde Bello, visited affected areas in Ijebu-Ode and Ijebu-Igbo to assess the situation.
Bello reportedly linked the latest occurrence to underground gas emissions previously recorded in Ijebu-Ode since April 2026.
He said the situation was under control and assured residents that the government was working towards a lasting solution.
According to Bello, government investigations had suggested that the phenomenon was a natural occurrence associated with geological and tectonic fault lines, rather than sabotage or a gas pipeline leak.
He urged residents to remain calm, adding that the affected students were expected to recover after receiving medical attention.
Bello also advised residents exposed to the gas odour to cover their noses and mouths with wet handkerchiefs rather than wear nose masks.
