An explosion rocks Downtown Schenectady late Thursday night. It happened around 10 p.m. near Frog Alley.

According to National Grid, an unground transformer failed near Church Street.

No injuries or damage to buildings have been reported.

National Grid crews have been on the scene all night and are working on repairs. They estimate it can take up to 24 hours to have everything fixed.

Portions of State Street near the highway ramp will be closed. People are urged to avoid the area if possible.

National Grid says once they remove the damaged equipment, they can determine what caused the failure.