The envelope that arrived at the Bright House Networks office Wednesday morning contained a one-sentence note.
"Goodbye friends," it said, a reference to the cable provider's marketing slogan, "Hello friend."
White powder fell on the worker who opened the envelope.
Though the powder turned out to be calcium carbonate, a harmless compound, the incident sent two workers to the hospital and brought out the hazmat team.
The workers, Bright House spokesman Joe Durkin said, were hospitalized, "out of an abundance of caution." They included the employee who touched the powder and another who complained of nausea, county officials said. The other 60 or so workers, mostly data processing employees, were sent home for the day.
Pasco County emergency workers responded and called in the Hillsborough County hazmat team to investigate.
Pasco County spokesman Doug Tobin praised the Bright House staff's response.
"It was a textbook approach to how to handle this type of situation," he said.
Pasco County sheriff's spokesman Eddie Daniels said the envelope was mailed to a Bright House office in Pinellas County and then routed to the Wesley Chapel office.
Shortly after noon, two hazmat workers in white protective suits went inside. About an hour later, they emerged with two clear plastic bags and a silver container that resembled a paint can.
"You're clear," one of the rescue workers told a Bright House employee.
The office is expected to reopen today.