In this photo taken Dec. 12, 2014, and provided by the U.S. Geological Survey, the active lava flow front continues to advance downslope towards the northeast about a mile and a half from the marketplace in Pahoa, Hawaii. Officials say lava from Kilauea volcano is on course to reach a supermarket and shopping center in the small town of Pahoa in seven to ten days. Hawaii County Civil Defense Director Darryl Oliveira said Monday, Dec. 15, 2014, the lava is about one mile away from Malama Marketplace supermarket. There's a hardware store, pharmacy and gas station in the same shopping center. (AP Photo/U.S. Geological Suvery, Tim Orr)

Lava from a volcano on Hawaii's Big Island is on course to reach a shopping center with a gas station and a supermarket in seven to 10 days, officials said Monday.

Lava is about 1 mile from the shopping center in the small town of Pahoa, said Hawaii County Civil Defense Director Darryl Oliveira. The also contains a hardware store, pharmacy and auto repair shop.

There's still a great deal of uncertainty about when the lava might reach the center and what it could hit. The lava could smother one structure in the complex or cover them all, he said.

"It just depends on what the flow does as it comes through," he told reporters during a conference call.

Oliveira says the county has been in touch with the merchants about . The county hasn't yet advised them to leave.

The supermarket, one of the biggest stores in the center, plans to start removing equipment on Tuesday and shut down on Thursday. Malama Market said in a statement it was encouraging customers to keep shopping until its doors close.

The would sell its remaining fuel and pump out what's leftover if it does have to evacuate, Oliveira said. It would then fill its tanks with water and firefighting foam.

This plan has been approved the U.S. Environmental Protection Agency and by the state Department of Health, he said.

An earlier idea called for the gas station to put sand into the tanks, but this wouldn't have removed all flammable vapors. It also would have destroyed the pumping system. By using firefighting foam, the gas station may use the tanks again if lava bypasses the area and it wants to reopen.

In this photo taken Dec. 12, 2014, and provided by the U.S. Geological Survey, a geologist uses a handheld GPS unit to mark the lava flow margin coordinates in Pahoa, Hawaii. Officials say lava from Kilauea volcano is on course to reach a supermarket and shopping center in the small town of Pahoa in seven to ten days. Hawaii County Civil Defense Director Darryl Oliveira said Monday, Dec. 15, 2014, the lava is about one mile away from Malama Marketplace supermarket. There's a hardware store, pharmacy and gas station in the same shopping center. (AP Photo/U.S. Geological Suvery, Tim Orr)

Lava has never hit a gas station on the Big Island in the past, Oliveira said.

Lava has been threatening Pahoa town, which has a population of about 900, for months. In October, it burned a house and covered part of a cemetery but stalled just before hitting Pahoa's main road.

It later started flowing from a different spot.

The could still cross the town's main road and a highway, which would make it more difficult for residents of Pahoa and the broader community of Puna to get to other parts of the island.