WASHINGTON

A UN official has warned of "very significant levels" of contamination of the rubble in Gaza with explosive ordnance, saying its clearance is costly.

In an interview with US magazine The New Yorker released on Wednesday, Charles Mungo Birch, chief of the UNMAS mine action program in the Palestinian territories, said more unexploded missiles and bombs have fallen in Gaza than anywhere in the world since at least the Second World War.

"We can’t quantify the level of contamination because we haven’t been able to do an assessment yet, but we can say that Gaza is eighty-seven per cent urbanized. Urban clearance is very expensive and very time-consuming," said Birch.

Estimates suggest that there are approximately 37 million tons of rubble in Gaza, where Israel has killed more than 34,000 Palestinians since last October.

"It is likely that much of it will be contaminated with explosive ordnance. As a rule of thumb, the U.N. assumes that ten per cent of ordnance fail to function. The bombardment and fighting have been very heavy in certain areas of Gaza, so there are likely very significant levels of contamination," he said.

The UN official said in a statement last month that it would take millions of dollars and many years to decontaminate Gaza from unexploded munitions. "We estimate that, to begin the clearance of Gaza, we need around $45 million," he said.

In mid-April, the UN agency for Palestinian refugees UNRWA said it "significant challenges in operating safely due to the presence of unexploded ordnance (UXOs), including 1,000-pound bombs inside schools and on roads" after Israel pulled troops out of southern Gaza's main city Khan Younis.

- Challenges in urban areas

Asked why urban areas are so much more difficult to clear, Birch cited the rubble and all the associated hazards.

"There’s an estimated eight hundred thousand tons of asbestos in the rubble. Then, you’ve got the human remains, about which the estimates vary, but many thousands of bodies are likely stuck under the rubble. You have to obviously handle that humanely, but they also pose a hazard," said Birch.

"Then, there are hazards from chemicals and from industrial processes. Hospitals can be a problem, too, when clearing unexploded ordnance because of the associated hazards: radiology departments, biological waste, et cetera," he added.

He said that because of the situation in Gaza, the UN authorities would not be able to train Palestinians in explosive-ordnance disposal techniques.

"So all the work will have to be done by international staff, which is very expensive," he added.