Dhanbad, Dec. 7 -- A National Disaster Response Force (NDRF) team from Ranchi carried out an extensive survey in Dhanbad's Kenduadih region on Sunday, following reports of gas seepage, and detected elevated levels of carbon monoxide in certain pockets of Naya Dhowra, officials familiar with the matter said.

The reported toxic gas leak in Rajput Basti under the Kenduadih colliery belt left two women dead and forced the evacuation of hundreds of residents since last Wednesday.

On Sunday, the NDRF team recorded a CO concentration of 1,680 parts per million (PPM), a reading officials described as one that requires close scientific monitoring, though precautionary steps have already been put in place.

Officials said the 32-member NDRF unit ...