A construction worker in Boston escaped with only a broken arm after falling nearly 35 feet from a building Monday morning.

What protected him? The plastic sheeting covering the construction site.

The worker, who was not identified, was working on the building when he lost his balance and fell through the wooden planks of the scaffolding, Steve MacDonald, a spokesperson for the Boston Fire Department, told ABCNews.com.

He did not hit the ground. Instead, the plastic covering the site to keep in heat and dust broke his fall.

"The plastic was covering the entire side of the building and engulfed him," MacDonald said. "We had to slice the plastic away so the medics could treat him."

The worker was treated at a local hospital for his injured arm.