LAND O’LAKES, Fla. — Officials in Florida said Saturday a sinkhole that swallowed two homes last month is growing.

Pasco County officials during a news conference that a large chunk of the hole’s edge has collapsed. Two more homes in Land O’Lakes, a Tampa suburb, have been condemned. The sinkhole, which opened up July 14, is now about 260 feet wide at its widest point. Officials aren’t sure what caused the destabilization, but think seismic vibrations from trucks and construction equipment around the hole could be to blame.

Dump trucks are scheduled to bring in boulders to try to stabilize one side of the sinkhole so a small barge can be brought in. Authorities hope to create a boat ramp so they can work from the barge, which will float on water in the sinkhole.

However, Kevin Guthrie, assistant county administrator of public safety in Pasco, said widening was expected with increased activity and there’s no reason to believe the hole is active.