The U.S. Postal Service says a leaking package of eucalyptus oil was behind Monday's evacuation of the Ybor City post office.

According to Tampa Fire Rescue, crews responded to the post office at 2000 E 12th Ave. shortly after 10 a.m. after an employee called 911 to report a package that was leaking. The leaking package was taken outside of the building by one of the employees.

Police officers and firefighters then evacuated the building and secured the scene. Emergency crews began decontaminating employees as a precaution while hazardous materials crews tested the substance.

Crews then determined the liquid was eucalyptus oil, which officials said can cause skin irritation or rash. In some cases, eucalyptus oil can also cause asthma-like symptoms.

Officials said the first person who came into direct contact with the package complained of some mild irritation on his hands.

Fifteen employees were set to be transported to Tampa General Hospital as a precaution, but officials said that after they explained the risks of exposure to those employees, none of the employees were taken to the hospital.

One employee had a mild asthma attack on scene, but that person was treated by paramedics and refused to go to the hospital. Another employee was helping with clean-up when he got bleach in his eye. That employee also refused to go to the hospital.

A spokesperson for Tampa Fire Rescue said firefighters were prepared to treat the employees as if the incident had been a "serious exposure."

The facility reopened around 1:30 p.m.