PARIS (AP) — Workers are gradually returning to Notre Dame Cathedral to clear out hazardous debris and consolidate the fire-damaged medieval monument, after a month-long delay prompted by fears of lead contamination.

A Culture Ministry official said the work is starting to resume Monday. Strict new lead-protection measures for workers include disposable clothing and a new decontamination zone to ensure their activities don't generate any pollution outside the site.

The consolidation work is a crucial first step to ready the fragile cathedral for reconstruction.

Hundreds of tons of lead melted in the April fire, spewing toxic dust into the air. Some environmental activists and residents say authorities underplayed the lead poisoning risks in the aftermath.

The Paris regional administration ordered cleanup work halted in July pending new worker-protection measures. They are among several lead-prevention operations underway in the area.