At dawn on that Sunday morning, the sea-going tanker Murachi, belonging to Maraven, a subsidiary of PDVSA, was moored off the power plant in Tacoa - a seaside village in Vargas state - preparing to unload 15,000 tons of fuel oil. Tank number 8, a cylindrical atmospheric storage tank 55 meters in diameter and 17 meters high, perched on a hill above the plant, was scheduled to receive the fuel. Two operators climbed to its top for routine pre-delivery checks, including a manual level reading. The manual reading was necessary because the remote level-reading instruments were faulty - one of many maintenance failures the investigation would later catalogue. When they opened the gauging hatch, hot hydrocarbon vapors mixed with air and created an explosive atmosphere. The resulting blast ripped off the tank's conical roof and killed both operators instantly.

The investigation pieced together a chain of failures that transformed an inert liquid into a bomb. The tank had been heated by steam coils to keep the viscous fuel pumpable, but on the night of December 18, a high-temperature alarm had triggered, indicating the oil had been heated beyond safe limits - plant historians later showed temperatures reaching 88 degrees Celsius, well above the 71-degree flash point. One coil was shut down in response, but the damage was done. Worse, investigators theorized that the fuel oil had been improperly blended with lighter petroleum fractions, introducing volatile components with low flash points. This blending did more than make the fuel flammable; it gave the mixture the wide range of boiling points necessary for a boilover - a phenomenon normally associated with crude oil, not refined products. The ignition source was never definitively identified, though speculation centered on a non-intrinsically safe lamp or a match used to illuminate the level dip tube.

A boilover occurs when a layer of superheated water trapped beneath burning oil flashes to steam, hurling the burning liquid outward in a violent wave. When tank number 8 boiled over, the burning oil cascaded down the hillside. Firefighters, civil defense workers, journalists covering the fire, and civilians who had gathered to watch were caught in the surge. The toll was devastating: 40 uniformed firefighters, dozens of civil defense workers, 17 plant employees, 10 media workers, and scores of civilians. The exact count was never established, but estimates consistently exceed 150 dead. The boilover itself ironically extinguished the fire in tank 8 by drawing in a sudden rush of air. But the burning oil that overflowed into the downhill containment dike ignited a sustained fire around tank number 9, another heavy fuel oil tank. Fearing a second boilover, the army evacuated 40,000 people from the surrounding area. Tank 9's fire burned for two to three days before exhausting itself.

The investigation painted a portrait of systematic neglect. The plant had no fire detection system. Its foam distribution pipework was corroded. Some fire pumps were nonfunctional. The fire hydrant connections were incompatible with the hoses carried by the responding fire departments. Access roads to the tank farm were inadequate for emergency vehicles. Houses had been built immediately surrounding the tanks - a land-use failure the investigators attributed to negligent authorities. In December 1984, Judge Maria Teresa Salazar issued eight arrest warrants against company executives on charges of manslaughter. None of them went to jail. Electricidad de Caracas eventually implemented safety changes, and the disaster contributed to improved global awareness of boilover hazards in petroleum storage. But for the families of the firefighters, journalists, and bystanders who had come to Tacoa that Sunday morning expecting to watch professionals handle a contained fire, the lessons arrived far too late.