LEGAZPI CITY (AFP) – Mount Mayon sprayed volcanic ash over a wide area Tuesday, raising new health fears for thousands already nervously awaiting an eruption that scientists say could come any day.

Thick clouds and occasional rains in the past days have also been giving local disaster officials the jitters, saying a heavy downpour might again trigger mudflows which three years ago killed more than 1,000 people living in the declared danger zones of Mayon Volcano.

The volcano continued to rumble as it emitted clouds of soot that left a layer of ash on nearby villages, officials and eyewitnesses said.

''The main problem of the eruption from a distance is the fine ash which is being generated by the collapse of rock fragments from the lava flow,'' said Renato Solidum, head of the Philippine Institute of Volcanology and Seismology (Phivolcs).

''It's not very thick, just a few millimeters of ash but that is the most dangerous part because it is very fine ash,'' he warned in a television interview.

Department of Health officials warned the tiny particles could cause respiratory problems or skin diseases and eye infections, and could even affect the thousands of people crammed into evacuation centers outside the eight-kilometer extended danger zone.

Eyewitnesses reported ashfall as far as ten kilometers from the restive volcano in Albay province some 330 kilometers south of Manila.

DOH chief epidemiologist Dr. Eric Tayag said residents should stay indoors to avoid being exposed to the ash. He said anyone who had to venture outside should wear long-sleeved clothes and cover their nose and mouth with a damp cloth.

Mayon, which has been oozing lava and spewing ash for a week, remains at alert Level 4, meaning it could violently erupt any day, Solidum said.

The 2,460-meter volcano, which is famed for its near-perfect cone, has erupted 48 times in recorded history. In 1814, more than 1,200 people were killed as lava buried the town of Cagsawa.

The belfry of the town’s buried church has since become a tourist attraction.

Mayon on Monday emitted lava fountains, powerful booming noises and other signs of an approaching eruption. But authorities are having trouble keeping villagers away from their homes and farms, said Albay Gov. Joey Salceda.

"There are people who have been evacuated three times, and we sigh: 'You again?'" said Salceda. "We've been playing cat and mouse with them."

The emission of sulfur dioxide — an indication of magma rising inside the volcano — jumped to 6,000 tons per day from the normal 500, Phivolcs said.

A major eruption could trigger pyroclastic flows — superheated gas and volcanic debris that race down the slopes at high speeds, vaporizing everything in their path. More extensive explosions of ash could drift toward nearby towns and cities.

In Mayon's other eruptions in recent years, pyroclastic flows had reached up to six kilometers from the crater, Salceda said.

"The probability of survival in an eruption is zero if you're in the danger area. The solution is obviously distance," he told the AP.

Rains would also complicate the problems.

However, Cedric Daep, executive officer of the Albay Provincial Disaster Coordinating Council, said they can presently heave a sigh of relief after the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said there would be no heavy rains in the next few days.

“But we are closely monitoring the weather condition here. PAGASA advice is only good for a few days, we don’t know what will come next,” said Daep.

“We are hoping that there would be no heavy rain because if it happens, that would mean another hazard,” he added.

Daep and other local disaster officials fear a repeat of the massive flow on the southeast side of Mayon in 2006 that killed more than 1,000 people, some of whom have never been recovered.

Heavy rains triggered by typhoons “Reming” and “Milenyo” that year loosened the stockpile of ashes on top of the volcano and washed away several communities at the foot of Mayon.

As of 11 a.m. Tuesday, a total of 9,441 families (45,366 persons) out of the target 9,946 families (47,285 persons) have already been moved out of the six-kilometer and eight-kilometer permanent and extended danger zones and were transported to at least 26 evacuation centers.

There are 505 families or 1,919 persons remaining, but Daep said there’s no need to evacuate them at this point since their location are safe from cascading hot lava and pyroclastic materials.