VOLCANO, Hawai'i — Hundreds of visitors and staff at Hawai'i Volcanoes National Park were evacuated yesterday morning by park officials worried about the potentially toxic effects of emissions from Pu'u 'O'o and Halema'uma'u crater.

Voluntary evacuations were announced for some towns and subdivisions near the park, but few people actually left those areas.

Vog was visible to a much lesser extent yesterday on other islands, including Maui and O'ahu, but air quality on those islands and on most of the Big Island was well within federal guidelines, health officials said.

Civil defense officials at 9 p.m. Monday announced voluntary evacuations for five communities northeast of Halema'uma'u crater because sulfur dioxide fumes were expected to intensify at midday yesterday.

The fear was that west winds would push the fumes into the Mauna Loa Estates, Ohia Estates and Volcano Golf Course subdivisions as well as the Volcano Village and Keauhou Ranch areas.

That sequence played out pretty much as the computer model had predicted except that the sulfur dioxide plume primarily stayed at about 1,000 feet, and mostly blew over the threatened communities, said Big Island Mayor Harry Kim.

"I'm glad for that," Kim said. "We still remain on alert and we're going to monitor 24/7 to make sure people are safe. The weather is very unpredictable."

By 4:30 p.m. yesterday, Big Island Civil Defense said evacuations were no longer necessary outside the park, although such areas remained on high alert.

For some Upper Puna residents, the risk from fumes was too high, and they evacuated yesterday.

Shirley Golden, a 14-year resident of Glenwood, said she suffers from asthma and emphysema, and left her hens and fish unattended while she stays at a American Red Cross shelter set up at a county pavilion in Hilo.

"I miss my house, but what can I say? What's more important? I only get one life," she said. "The vog is so thick, I cannot see the road."

Only four people had taken shelter at the pavilion, Auntie Sally's Kaleohano's Luau Hale, by yesterday afternoon.

MOST SHRUG OFF VOG

Most Volcano area residents said they had seen far worse vog or volcanic haze before, and saw no reason to leave. Golfers played the Volcano Golf Course yesterday afternoon while residents walked their dogs or worked around the house.

Volcano resident Linda Ugalde and her husband were ready with gas masks but didn't plan to leave.

"It's not any thicker than we have had before," Ugalde said. "It's been gorgeous all day. I can taste a little bit of sulfur in the air, and I can see the plume from my front door."

Instead of evacuating, Ugalde's husband was digging in a backyard garden.

"I'm very reluctant to evacuate, especially when it's still very livable, and I think part of that is because it's been on the news now. We would just be a target for break-ins," she said.

Another consideration was the family pets, which include dogs and a goat. "We have too many animals, and from all reports I've heard, Hilo for most of the morning was worse than we are here," Ugalde said.

Hilo resident Rainer Santos joked that he came to Volcano to get a whiff of fresh air.

Hilo and many Puna residents awoke to find their homes enveloped in a thick layer of vog yesterday morning, with particularly high spikes in sulfur dioxide recorded in the Fern Forest subdivision and at the Volcano Village Fire Station.

Santos said his 18-year-old daughter suffered headaches and difficulty breathing in Hilo in the morning, but that Volcano in the afternoon was more clear and pleasant.

Hilo and Puna residents got relief by midmorning as winds pushed some of the emissions out to sea or toward the leeward side of the Big Island.

Pu'u O'o on Kilauea's East Rift Zone has been producing about 2,000 metric tons of sulfur dioxide a day for years, while only about 200 tons per day were being released at Halema'uma'u at the summit. Sulfur dioxide emissions from the summit began to climb late last year, and by March 13 had climbed to record levels of 2,000 tons a day as a new vent opened in the wall of the Halema'uma'u crater.

Emissions at the summit yesterday dropped to about 800 metric tons, Kim said, but the shifting winds meant that even the reduced emissions threatened Volcano Village and the park.

HOTEL, CAMP EMPTIED

The evacuation order for the national park included the Volcano House hotel and the Kilauea military camp, which had 180 guests. Guests at both places were moved to Hilo. Only essential staff remained on duty at the park.

"The park will reopen when favorable winds return, and sulfur dioxide levels diminish in the area," according to a statement from the park.

The park was closed to all visitors, with rangers turning away a steady stream of disappointed tourists at the main gate, including Greg Prather and his family, residents of Calgary, Alberta. The Prathers stood at a guardrail on the Volcano Highway watching the plume of fumes and ash rising from the crater in the distance.

"They said that the plume has a concentration of poison gases and they were concerned that it might descend because of the lack of trade winds and so people could get hurt," Prather said. "We thought, 'OK, we're not going to argue.' "

Lt. Col. Trey Johnson, commander of the 93rd Civil Support Team of the Hawai'i National Guard, said the hazard model being used to project the potential threat suggests that a relatively narrow plume of sulfur dioxide at levels well above the federal air quality standards will extend out to about 30 miles west of Halema'uma'u crater.

Although that could severely affect communities around the volcano, Kim said, it will likely not impact North Kona, where many more people live.

"Fortunately, there's nothing between there and Kona, as far as populated areas," he said. "We have a great distance factor of no people."

The model suggests the sulfur dioxide will dissipate considerably before it reaches that heavily populated area, Johnson said.

Civil defense officials said the communities around the volcano remain at Code Purple, meaning everyone should avoid outdoor activity and people with respiratory problems should leave the area.

The wind will determine whether other islands continue to get a lighter version of vog.

"A lot has to do with the wind conditions throughout the state," said Willie Nagamine, the state Health Department's Clean Air Branch program manager. "We get the vog from southerly winds that blow from the Big Island up the chain."

However, the harmful sulfur dioxide fumes are not expected to blow toward O'ahu, Maui or Kaua'i, Nagamine said.