FINANCIAL DISTRICT, Manhattan (PIX11) — This May marks the 20th anniversary of the end of the clean up and recovery efforts at Ground Zero.

Thousands, including first responders and sanitation employees, worked on that day and in the months afterward. Many are still suffering and dying from injuries.

Sanitation crews are being honored with a documentary about their roles. It’s currently in production. There was a special screening Monday at The 9/11 Memorial Museum.

The Sanitation Foundation is a non-profit organization formed in 2016 to support workers and the mission of the department. It’s supporting the documentary project.

Martin Bellew retired with more than two decades at the Department of Sanitation.

“We were instrumental moving materials and opening it up,” he said.

DSNY crews transported 1.6 million tons of debris from the site to a facility created at Fresh Kills Landfill on Staten Island. The clean up, sorting and registering took nine months.