BOSTON -- A series of frightening incidents on city streets has Boston Mayor Tom Menino steamed.

NewsCenter 5's Gail Huff reported that after leaving the New England Aquarium, a 6-year-old boy received second-degree burns on his leg while walking over a steaming hot manhole.

A burst pipe underground was to blame for the steam that was so hot it blistered and burned the boy's leg.

Menino sent a letter to energy company Trigen-Boston demanding that antiquated pipes running under the city be repaired to correct the ongoing problem.

In the past couple of years, a 2-year-old boy and a woman were also both seriously burned in separate, similar incidents.

Menino wrote to the company, which owns more than 20 miles of underground pipelines, "The numerous steam-related malfunctions pose risks to public safety, impair the quality of life for our residents and visitors and require costly intervention by the city."

Trigen is a private company.

The mayor wants legislators to pass a law requiring steam companies, such as Trigen, to be regulated by the state.