PELHAM, N.H. (CBS) – Investigators now say 13 people were hurt in a huge fireworks explosion at a home in Pelham, New Hampshire Tuesday night.

In a brief statement released Friday morning, Pelham police increased the total, noting that eight adults and five children were injured in the blast in Chris Pappathan’s backyard.

Two adults and one child are still being treated at hospitals in Boston.

The child most seriously injured is slowly improving, a family spokesman said Friday.

Two-year-old Ben Bertini was placed in a medically induced coma to help him recover from his wounds.

Jessica and her son Ben Bertini (Family photo)

“It looks like he’s going to require some minor skin grafts, but they’re expecting a full recovery, with minimal scar tissue,” spokesman Ed Gleason told WBZ NewsRadio 1030.

“Overall, it’s very encouraging in terms of what it could have been.”

Ben’s grandmother, Linda Bertini, said he is expected to be in the hospital for at least a month with second and third degree burns on his arms and legs.

Police said they are still interviewing guests and witnesses to find out what caused the explosion.

Two funds have been set up at two local banks for some of the victims:

1. Bertini Fund

Enterprise Bank

PO Box 1038

139 Bridge Street

Pelham, NH 03076

Checks payable to:

FBO Friends of Ben Fund

2. Friends of Foy Family

Enterprise Bank

1168 Lakeview Ave.

Dracut, MA 01826