Some of the operations have their required permits but skirt the rules. Thirteen scrap operations told the Los Angeles Regional Water Quality Control Board —implausibly — that there was no need to test their runoff for toxic substances, as required, because it hadn't rained enough over the course of the year to come up with a sample.
"We're a poor agency, with limited resources for enforcement," said Sam Unger, executive officer of the water board, which has six inspectors to oversee more than 5,000 industrial facilities and construction sites.
In general, regulatory agencies do not routinely inspect scrap metal sites. They act mainly in response to accidents or complaints.
Some in the industry blame rogue operators for the problems.
"We want to operate responsibly, but the other people don't," said Mona Howerton, who helps her husband run Williams Recycling in the Florence-Firestone area. "And they get away with it."
Others point out that metal recyclers create jobs and new uses for materials that otherwise would end up in landfills.
Scrap metal is "one of the few exports that is contributing positively to our balance of trade," said Kevin Lawlor, until recently a spokesman for the Washington, D.C.-based Institute of Scrap Recycling Industries, which represents 1,600 companies.
With factories in developing Asian countries hungry for steel and other metals, scrap metal has become one of the largest U.S. exports, worth $7 billion a year in California alone. Much of the cargo moves through the ports of Los Angeles and Long Beach.
The price of steel scrap, for instance, has shot up from $75 a ton in 2001 to about $300 now. Dozens of operations have opened to melt metal down, cut it up and bundle it. Nationwide, scrap exports rose from 6 million tons in 2000 to more than 18 million tons in 2007, according to a federal report.
"We buy scrap," signs read in English and Spanish along Alameda Street. Some of the operations focus on cars, and others, such as United Alloys, on specialized metals including titanium and tungsten. Most will take in many kinds of metal.
Recycling Unlimited in Wilmington has a typical setup: A small office sits near a mound of metal at least 10 feet high, with box springs, shells of old cars and pieces of rebar poking out at odd angles. Because of patchwork zoning, these businesses sometimes sit right next to single-family homes, some of which are coated in a thin layer of metal dust.
The most obvious dangers are to workers and close neighbors, as was underscored by a succession of accidents in the summer of 2010.
On June 5, a fire broke out at the Pick-Your-Part yard in Wilmington, a car recycler. It took firefighters 30 hours to put it out.
Three days later, at Tulare Iron & Metal in the Central Valley, a worker began to cut up a gas canister without checking to make sure it was empty. Within minutes, a yellow-green cloud of concentrated chlorine gas had enveloped the facility.
"Oh my God, I'm dying," Beverly Martinez recalled thinking as she staggered out of the office, half-carrying one co-worker while another hung onto her shoulders. She and more than 20 others were injured, six of them hospitalized.
Then came the two fires at United Alloys in South Los Angeles.
Company officials, who had the required permits to operate, declined to comment on either incident.
After the first fire, Cal/OSHA fined United Alloys $6,020, finding among other things that unsafe use of a spark-producing power tool had led to the blaze. The fine was later reduced by more than half.
In September 2010, a fire broke out at Recycling Unlimited in Wilmington. An explosion broke windows at a home nearby and cracked the wall of another, according to neighbors.
Interviewed outside her tidy bungalow, the woman whose wall cracked said there had been explosions on other occasions as well. But the woman, who spoke on condition of anonymity because she feared retribution, said she was more concerned about dirty water that pours from the pile of metal when it rains or the yard is washed.