36 Injured After School Bus Overturns in the Bronx: 'No Students Were On the Bus,' Says N.Y.C. Mayor

A school bus carrying dozens of adults overturned on a highway in New York City Thursday morning.

Shortly before 6 a.m., a bus going northbound on the Hutchinson River Parkway in the Bronx overturned while trying to exit, a New York Police Department spokesperson told PEOPLE, noting that all the adults were employees of the bus company.

The bus was carrying 37 people, including the driver, at the time of the incident, according to WABC-TV, NBC New York and Fox station WNYW.

33 people were taken to local hospitals with minor injuries, while an additional 3 people were hospitalized in serious but stable condition, a spokesperson for the New York Fire Department told PEOPLE.

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The driver of the bus, who was issued a summons for dangerous driving, refused treatment at the scene, an NYPD official said, according to NBC New York.

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In a statement, New York City Mayor Eric Adams confirmed that "no students were on the bus" at the time of the incident.

"This morning, a school bus carrying only bus drivers for the city's summer programming overturned while exiting the Hutchinson River Parkway," Adams wrote, adding that "Families should expect that some bus routes this morning and afternoon will be delayed, and schools will be reaching out to families whose routes are impacted."

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The bus operator, Consolidated Bus Transit, told the NBC New York in a statement that it was investigating the cause of the incident, which is under investigation.

"Right now our immediate concern is for the safety and well-being of our employees," the statement said. "Consolidated prides itself as a safe and reliable transportation company providing transportation services in New York City for over 40 years. We will work with the police and Department of Education in determining the cause of the accident."

Consolidated Bus Transit did not immediately respond to PEOPLE's request for comment.