MONTPELIER, Vt. – Passengers on a May 30 bus from Boston to Montreal may have been exposed to tuberculosis, health officials in Vermont and Massachusetts said Tuesday.

At least some of the passengers of the Vermont Transit Co. trip were being notified that another passenger on the bus may have had the disease.

“We had an alert from the Boston, Massachusetts, Department of Health,” said Chris Andreasson, general manager of Vermont Transit Co. Inc. “The only concern they had was for somebody that sat next to passenger for a long period of time.”

Andreasson said Thursday the company’s bus drivers had been tested and cleared of the disease.

The Massachusetts Department of Public Health was coordinating the investigation but did not provide any information Tuesday.

The Boston Public Health Commission had a Boston passenger and bus driver tested for the disease, said spokeswoman Ann Scales.

The test results were confidential, she said.

This spring an Atlanta attorney caused an international health scare after he flew to Europe after he had been told he had a drug-resistant form of tuberculosis.

Andreasson said he was told the bus passenger’s possible infection was not as serious as the case of the Atlanta man.

The Vermont Department of Health was notified last week and determined that no Vermont passengers were on the bus.

“The person in all likelihood was contagious,” said Dr. Cort Lohff, Vermont state epidemiologist, who could not recall a case in Vermont where passengers were notified after a contagious person boarded a bus or plane in the state.

Being on a bus or airplane with an infected person, “that really increases the chance of being exposed to tuberculosis. The amount of time you may be exposed to someone may be a factor. Other factors play into the role of how infectious this person was,” Lohff said.