Dangerous carbon monoxide fumes filled a Lehigh Valley hotel on Sunday for the second time in three months.

Fumes swept through the Best Western in Upper Macungie Township at about 12:15 a.m.

All guests were evacuated. No one was injured.

After about four hours, everyone was allowed back into the hotel.

In January, Phillip Prechtel died at the hotel when he was overcome by carbon monoxide fumes. Excess levels of CO sickened 10 other people, including his wife, Katherine.

Investigators said the poisonous fumes originated from basement water heaters. Plastic construction tarps put up by a subcontractor doing repair work on the building trapped the fumes coming and pushed them back inside the hotel.

The hotel installed CO detectors in each of its rooms after Prechtel's death.

There was no word on what caused Sunday's incident.