MEXICO CITY — Mexican state oil monopoly Petroleos Mexicanos on Monday announced it had recovered about two-thirds of the estimated 5,000-barrels of oil that spilled last week into a river feeding the Gulf of Mexico.

But major work remained to be done near the source of the spill on the Coatzacoalcos River in southern Veracruz state, according to a federal environmental regulator and Petroleos Mexicanos, or Pemex.

The spill occurred after an explosion Wednesday at a pumping station near Santiago Tuxtla, about 250 miles east-southeast of Mexico City. The blast caused a burst of high pressure that ruptured the oil line 70 miles (110 kms) away in Nanchital, just south of the Gulf port city of Coatzacoalcos.

Four of the five people injured in the explosion remained hospitalized Monday in Mexico City and Coatzacoalcos, with one man in grave condition, according to a news release by Pemex.

The most visible progress in the cleanup is along the southern Gulf Coast, where the oil reached about 40 kilometers (25 miles) of beaches, according to Mexican Environment Department Delegate Francisco Moreno, who surveyed the cleanup progress from the ground and air on Monday.

Moreno said about 90 percent of the oil along the coast has been removed.

Pemex announced that the beaches of Coatzacoalcos and Allende, which straddle a still heavily polluted river, are completely clean.

About 4,400 cubic meters of lilies and other oil-soaked vegetation had been cleared from the Coatzacoalcos River, as a state university begins to study the impact of the spill on the river and coastal ecosystems, Moreno said.

The state oil company estimated it had collected about 45 percent of the 11,000 cubic meters (390,000 cubic feet) of material soaked by the spill.

Prosecutors at the Environment Department are still considering a criminal complaint against Pemex, which could be fined it as much as US$200,000 (euro148,000) for the spill.

Reporting on the public-health consequences of the spill, Pemex said its medical services have treated 24 people at a company hospital in Nanchital and 59 patients in house calls after receiving reports of migraine headaches and irritation of the mouth, nose and throat.

About 300 people continue to work in the cleanup effort.

Source: Associated Press