NEW DELHI, India — In the post-apocalyptic West Delhi junk market of Mayapuri, Ram Kumar sits with a group of laborers like himself in the scant shade provided by a ramshackle shed.

Due to a mysterious radiation leak that has sent seven neighborhood residents to the hospital with radiation poisoning over the past week, business is slow, and there's no work for these loaders. But Kumar says he has no choice but to wait.

“You can't see it (radiation), you can't feel it, you can only imagine how contaminated the air is here,” said Kumar. “Everyone thinks of leaving, but where would we go?”

Recycling is big business in India, which imports as much as 3 million tons of scrap metal each year. But this week's radiation poisonings have shifted focus, temporarily, to the flip side of the fortune: Along with the towering heaps of steel and copper comes a mountain of hazardous waste — asbestos, lead, mercury and, it turns out, potentially deadly radioactive materials.

“Under metal scrap, almost everything comes in — be it radioactive material, be it ammunition, be it e-waste, hazardous waste, toxic waste,” said Kushal Yadav, head of the toxins unit at New Delhi's Centre for Science and Environment, a non-government think tank. “We don't really know what's coming in. It's only when such incidents happen that we come to know.”

On April 7, shop owner Deepak Jain and four others were hospitalized with radiation sickness after they were exposed to what initial press reports described as a bright, shining metal object. Subsequent investigations by the country's atomic energy regulators identified the radioactive material as Cobalt 60 — a metal used in the sterilization of medical equipment and for radiotherapy.

Before long, the team of scientists discovered 11 different sources of radiation in Mayapuri's scrap heaps, and an anonymous source at one of the investigating bodies told India's Mail Today newspaper that the Cobalt 60 was believed to be part of a larger, yet undiscovered consignment of metal.

This is not the first such incident, and will by no means be the last. Last year, high levels of radioactive metal were found in a shipment of stainless steel elevator buttons which were exported to Germany. And not long ago, a railway worker was seriously irradiated when he pocketed a shining object he discovered on the job.

Radiation poisonings are just the tip of the iceberg. Exposure to other forms of hazardous medical, electronic and industrial waste is so commonplace that no one keeps statistics about the associated health problems.

“In this incident around 10 people have been affected, but this is only a case where you have seen acute exposure,” said Yadav. “In terms of chronic exposure, which is happening over long periods of time, there are hundreds of thousands of workers exposed to tiny amounts of toxins every day, and it's affecting their health. This is never documented anywhere.”

According to a recent study by the Indian Institute of Management, Lucknow, only half of the 400,000 kilograms of hospital waste that India generates each day is treated before its disposal. Toxic Links, an NGO, estimates that as much as 50,000 tons of electronic waste is illegally imported each month, bringing with it lead, mercury, cadmium, beryllium and other hazardous materials, while Indian industry generates 6 million or 7 million tons of hazardous waste per year. On Indian shores, poor laborers — even children — climb its mountains in rubber sandals and tear it to pieces with their bare hands. And they do it for next to nothing.

Kumar and the other loaders in Mayapuri earn between $2 and $5 a day heaving clapped out drive shafts, truck tires, axles, steel pipe and all manner of scrap onto trucks and wagons. It's brutally hard work in one of the hottest Aprils on record — the mercury already nearing 110 degrees Fahrenheit. Even in the lee of the dilapidated warehouse, a hairdryer wind sandblasts the ragged workers with grit. The air smells of ozone and sweat and scorched metal. The danger is as bald-faced as the filth.

“Getting hurt is part of the job,” said Kumar.

Shop number DII-32, where the first pin made of radioactive Cobalt 60 was discovered, is now shuttered, a stack of Delhi Police barricades forgotten against the wall. But the scrap dealers on either side are still watching their workers sift and sort wire and pipe. Nobody seems unduly worried about being irradiated. The national Atomic Energy Regulatory Board has given the all-clear signal after repeated sweeps of the area. And, if anything, the shop owners are defensive about the safety of their trade.

“It's perfectly safe,” one dealer said. “Why should I be worried? I'm sitting in my shop. I don't have the hobby of going around with my notebook.”

With not a spot of grease on him, he's probably never in his life touched a piece of the scrap he sells.