SOUTH FLORIDA - A worker is feared dead after he fell nearly 150 feet Friday morning after the roof of the silo collapsed.

It happened in South Florida.

Search and rescue crews are trying to figure out how to rescue the worker.

The only way to enter would be for rescuers to repel in to the structure, which is already unstable.

Authorities say no contact has been made with the missing man.

A silo is a cylinder structure, up to 200 feet in length used for storing grains.