Thomas Johnson Elementary School in South Baltimore, which closed early on the first day of school Monday because its air conditioning wasn't working, will remain closed today.

Many city schools lack air conditioning, but Thomas Johnson does not have windows that open. As a result, "it is an absolute hot box," said Keith Scroggins, the school system's chief operating officer. "We don't want to take the chance that any children will get sick."

The system had a new cooling tower installed at Thomas Johnson this month, after summer school ended. After the tower went into operation last week, two parts in the chiller broke and "it just resulted in an overall failure," Scroggins said. He said crews are working to make repairs.