Ericka Martinez, a data entry worker and 20-year resident who lives a few blocks from the plant, said she sought help from the city of Paramount. Martinez said she and her neighbors did not know which agency to contact, so they started filing online complaints with the city two years ago about an odor she likened to someone lighting a match under your nose.
Since then, the odors have lessened at times, only to return a few weeks later, including on nights and weekends, she said. "It's not every day, but it's a problem that has not stopped."
Paramount City Manager Linda Benedetti-Leal said the city never received complaints about the odors.
Lappin's initial worries about foul air at the school were referred to the Los Angeles County Department of Public Health. Proving a direct link between a particular source of pollution and illnesses in a community is very difficult — and county health officials found no evidence of a cancer cluster in Paramount.
In 2012, Lappin turned to the air quality management district, which said it had received 64 complaints about Carlton over the last two years, three-quarters of them from Lappin.
Records show that the district had cited Carlton for violations six times over the last two decades, including for emitting excessive nitrogen oxides — smog-forming gases that can cause respiratory problems. In 2012 the facility was cited for failure to submit an annual report on its emissions.
Sam Atwood, spokesman for the air district, said his agency's response was "immediate and aggressive" once the recent complaints made their way to his agency. "In very short order, we not only had inspectors on the ground, but we also started to do air sampling," he said.
Last month the air district held a community meeting at which officials revealed that the odors were cause for concern. Air quality officials also told residents they have no specific rules governing metal grinding at Carlton and more than a dozen other similar operations in the region.
The district has begun drafting regulations that would regulate day-to-day operations at metal forging, shredding, grinding and processing facilities to better protect people who live, work and attend school nearby.
Angelo Bellomo, environmental health director for the county health department, said he remains concerned about the location of the school, even if his agency found no evidence of a cancer cluster.
"In addition to that one facility, there are many sources of emissions in that area, and the cumulative risk presented by these sources cannot be ruled out as contributing to illness in the community," Bellomo said.
"We are looking at other similar situations throughout the county where facilities may be in regulatory compliance, but where we nevertheless find there is a public health impact."