West Miami-Dade, FL – A carbon monoxide leak at a West Miami-Dade office building sent 17 people to the hospital and made dozens sick, Monday.

Miami-Dade Fire Rescue responded to the scene at the Lennar Corporation offices, in the area of Northwest 107th Avenue and Seventh Street.

Crews evacuated the building, and officials said they found the highest concentration levels of carbon monoxide on the second floor.

Paramedics treated between 25 and 30 people at the scene and transported 17 others were transported to area hospitals. “We are sending them to the hospital to get further evaluation, with different complaints from headache, dizziness, and readings are above normal, that require for them to be seen in a medical facility,” said Miami-Dade Fire Rescue Capt. Robert Betancourt.

One of the victims experienced severe respiratory distress and was taken to Kendall Regional Medical Center. Some of the others are being transported to Baptist Hospital for observation.

Miami-Dade Fire Rescue Chief Rogelio Vandamas said, even though crews have been able to ventilate the building, their current challenge is finding the source of the leak. “Until we find the source, if we don’t get the levels down, we are not going to reopen the building,” he said.

About 80 people were sent home because they felt sick. Approximately 400 people work at the building.