Jakarta. Indonesian nuclear agencies conducted decontamination operation over the weekend after radiation was detected at an area inside a housing complex in Serpong, South Tangerang, Banten province.

Workers have removed 79 drums of radioactive soil and cut trees and grass from an empty land at Batan Indah housing complex during the three days of cleanup until Sunday, an official said.

The housing complex is named after the National Nuclear Energy Agency (Batan), which runs an office and a reactor in the same town.

The operation involved officials from Batan, the Nuclear Energy Regulatory Agency (Bapeten) and the police.

"Our assessment using special equipment found radioactive substance called Cesium-137,” Bapeten head Abdul Qohar said.

Exposure to high level radioactive cesium can pose serious risks to human health, including cancer and death. It takes at least three decades to reduce its radioactivity by a half.

Abdul said Cesium-137 is used by various industries, including paper and steel. Investigation is underway to identify companies or individuals who used Cesium-137 in the country and dumped the toxic waste at the housing complex, he said.

Nine residents of the neighborhood will undergo “whole body” examination to check the level of radioactive exposure at a Batan facility on Monday.

Abdul said companies who hold license to use Cesium-137 are banned from storing or managing radioactive waste themselves. They must send it to Batan’s Center for Radioactive Waste Technology in Serpong.

The cleanup will continue until the radiation arrives at the level considered safe for humans, he said.

The Bapeten said earlier radioactive contamination at the housing complex was caused by illegal radioactive waste disposal, but they were in the dark about the alleged perpetrator.

“We can assure that the increasing radioactivity in the area has nothing to do with the [Batan] reactor,” Batan spokesman Heru Umbara said.

The housing complex is located about 45 kilometers from Batan’s Siwabessy Reactor.

He said any leak from the reactor would have impact in a wider area around it, not limited to the housing complex.

“Our investigation found that the radioactive contamination occurred underground,” he said.