Seven people returned home from the hospital after high levels of carbon monoxide were detected at their duplex early Monday morning.
Hollywood Fire Rescue responded to 1900 Thomas Street shortly after 5 a.m. and evacuated the duplex when detectors warned of high to lethal levels of the odorless and colorless gas.
"We called our hazmat teams up and they checked out, [and] they found very high numbers," said spokesman Joel Medina.
Officials said the carbon monoxide came from a tankless water heater in a bathroom.
Four adults and three children were taken to Memorial Regional Hospital. They returned home in the afternoon.
Two of dogs were also forced to evacuate the home.
Firefighters have been called to the duplex three times in the last three days.
"We've been here on the 4th, the 5th, and the 6th," said Medina.
Police also found a small amount of marijuana inside the home. No charges related to it are expected to be filed.