The tragic incident occurred on Thursday, May 28, after the victims were reportedly contracted to drain sewage from the school’s septic system.
According to preliminary reports, the three workers are believed to have lost consciousness after entering the confined septic tank, which allegedly had insufficient oxygen.
Authorities suspect the men may have suffocated before drowning inside the tank.
Witnesses at the scene said efforts to rescue the victims began immediately after the workers failed to respond from inside the septic system.
However, the operation proved difficult due to the dangerous conditions within the tank.
Rescue teams spent several hours retrieving the bodies from the septic tank as anxious residents and school staff gathered at the scene.
The bodies were later moved to a nearby hospital mortuary pending identification and postmortem examinations.
The incident has sparked concern over occupational safety standards, particularly for workers involved in hazardous confined-space operations such as septic tank cleaning and sewage management.
Police officers who visited the scene have since launched investigations into the circumstances surrounding the tragedy.
Investigators are expected to establish whether the victims had protective gear and whether proper safety procedures were followed before they entered the septic tank.
Authorities are also expected to determine whether the workers had received any training on handling hazardous environments and whether emergency rescue measures had been put in place before the operation began.
Cases involving deaths inside septic tanks and wells have been reported in different parts of the country in recent years, with experts often attributing such incidents to toxic gases, oxygen depletion and lack of proper safety equipment.
Occupational safety officers have repeatedly warned employers and contractors against allowing workers to enter confined spaces without adequate ventilation, protective clothing and monitoring equipment.
The deaths at Makindu Boys High School have left residents in shock, especially following reports that two of the victims were closely related.
Family members and local residents described the incident as heartbreaking and called for stricter enforcement of workplace safety regulations to prevent similar tragedies.
Leaders and residents from the area have urged relevant authorities to conduct thorough investigations and hold accountable anyone found to have ignored safety procedures.
The tragedy adds to growing concerns about the safety of casual labourers who often undertake risky manual jobs without adequate protection or insurance cover.