BOSTON (CBS) — The annual Cradles to Crayons backpack-a-thon is making sure thousands of kids in need have the right supplies to be ready for the new school year.

As the music kept spirits high, about 800 volunteers worked in a sweltering Reggie Lewis Athletic Center in Roxbury.

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Volunteer Beatrice Holdstein explained, “Back to school season is coming up and we just want to help out.”

Hundreds of volunteers came together in the Reggie Lewis Athletic Center to pack backpacks for Cradles to Crayons (WBZ-TV)

Lynn Margherio is the founder of Cradles to Crayons. She said, “There will be 42,500 backpacks packed out today…There are kids in so many cities across the Commonwealth who live in families that struggle to make ends meet.”

“We want to make it easier for parents to send their kids off with excitement and for those kids to have what they need,” Margherio continued.

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From notebooks and pens to rulers and erasers, volunteers from 40 local companies helped organize what kids need.

Volunteer Sydny Ferguson said, “It’s for the kids. Kids need school supplies. I’m into learning. I’m trying to go back to school, so why not help out.”

Volunteers packed 42,500 backpacks for kids in need (WBZ-TV)

“My daughter just finished kindergarten and I remember buying her supplies and my son before her. I think it’s great to have a backpack ready for kids when they start school so I really wanted to help,” said Josh Guthermann, another volunteer.

Volunteer Bob “Bubba” Lynch said, “The kids open these up and it’s treasure. It’s wonderful. We really enjoy doing it.”

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Cradles to Crayons started here in Boston in 2002. It has now expanded to Philadelphia and Chicago.