M. Ara Syaf, The Jakarta Post, Pekanbaru

Fires had charred 10,906 hectares of plantations and protected wildlife forest reserves in Bukit Batu subdistrict in Bengkalis regency, Riau, an official said on Tuesday.

Head of Riau's Environmental Impact Management Agency (Bapedalda) Naili Saidi said the relevant local agencies were considering ways to put out the fires or prevent them from spreading to other areas.

The authorities had also been conducting an investigation to find those blamed for starting the fires, and arrest them, he added.

Naili said his office needed more people to help with the fires.

"We have contacted the local forestry office and asked them to try to put the fires out, but we face an extreme lack of personnel," he said.

Naili said the damaged plantations included hundreds of hectares of peat land in Bengkalis. "If extinguished, only fires on the surface can be put out usually, while underneath the brush the fires are still smoldering and can spread."

Based on satellite monitoring, the Bapedalda head recently detected at least 222 separate fires across Riau.

However, Naili said on Monday that many of the fires had been put out following two days of heavy rain in Riau.

He said on Tuesday, that based on satellite observations, by the Forest Fire Prevention Control Project (FFPCP) based in the South Sumatra capital of Palembang, at least 100 fires were detected in Riau.

At least 69 of the them were near the town of Dumai, 17 near Bengkalis, seven in the Siak area and seven others near Rokan Hilir town, Naili added. In Malaysia, there were 10 fires still burning.

He warned that Riau could still be blanketed by even thicker haze between July and October, the height of the dry season. "These hot spots have been extinguished by the heavy rain over the last two days. We predict, however, that the smoke will return to Riau in the July-October period."

Naili also said the haze could once again affect Malaysia soon as the wind may blow from Riau toward the neighboring country later this month.

"We are worried that if these areas continue to smolder, smoke could get blown over to Malaysia as it did in 1997," Naili said.

Meanwhile, schools that closed in Bengkalis were reopened on Tuesday after the thick haze blanketing parts of the province receded in the regency.

Students from the oil-rich area of Duri in Mandau subdistricts in Bengkalis, returned to their schools inside the complex of foreign oil company PT Caltex Pacific Indonesia.

Caltex closed the schools on Monday as the thick haze reached an alarming level in Bengkalis.

Many people in Mandau had resorted to wearing masks outside their homes, while motorists used their lights during the day as visibility was reduced to only around 20 meters.

Caltex also once again raised a red flag signifying that the smoke covering Duri had reached dangerous levels.

Poedyo Oetomo, Caltex's communications and media relations manager, said that students attending schools under the management of his company had been given a vacation for as long as necessary to prevent them from suffering acute respiratory infections.

"The haze on Monday morning was quite thick, so we were forced to give students a vacation," he told The Jakarta Post.

"We have also hoisted a red flag, which means that the air pollution in this area is extremely hazardous."

Poedyo said Caltex had not yet allowed its thousands of foreign and domestic employees to stay away from work, although they had been ordered to wear masks.

"We don't have any plans to give the workers leave so far, nor to evacuate them, particularly in the case of the foreign staff. They are continuing to work as usual," he added.

Mandau subdistrict head A. Ridwan Yazid said on Monday that none of the public schools had yet followed Caltex's decision. "We have yet to receive a directive from our superiors to give the students a vacation."

He said the haze was continuing to thicken in his region, where the visibility is down to 20 meters also.

The smoke was believed to be coming from neighboring areas, he said, but did not elaborate further.

"The haze is worrying. Some residents have begun to wear masks, while some motorcyclists and car drivers are switching on their lights in the day time to avoid accidents," Ridwan said.