Formaldehyde Cancer Risk in Your Neighborhood
In most of the country, formaldehyde contributes more to outdoor cancer risk than any other toxic air pollutant. Look up your address to see risks from the chemical on your block and where it comes from.
Credit:
Lucinda Rogers, special to ProPublica
Formaldehyde causes more cancer than any other toxic chemical in the air.
It’s emitted from cars, trucks, planes, industrial facilities and many other sources. It’s also formed in the atmosphere when other chemicals combine in the presence of sunlight. Even if you don’t live in a high-traffic or industrial area, the geography and climate of your area could increase your cancer risk from formaldehyde because of this so-called “secondary formation.”
Read our story → | Read more about our analysis →
Top Blocks
Blocks with particularly high levels of formaldehyde cancer risk. Shuffle blocks ↺
Browse by State
See blocks with high risk levels by state.
About Formaldehyde Cancer Risk and This Database
ProPublica analyzed formaldehyde concentrations modeled by the Environmental Protection Agency and released through the agency’s AirToxScreen database and found that, in every populated U.S. census block, formaldehyde in the air poses an incremental lifetime cancer risk greater than one incidence of cancer in every million people, the limit that the agency aims to stay below for toxic air pollutants. Some 320 million people live in areas where that risk is at least 10 times higher. In other areas, the cancer risk from formaldehyde is even worse.
We’re making that data searchable in this interactive database.
AirToxScreen works by modeling a year’s worth of emissions (in this case, emissions in 2020) along with weather data and natural sources to approximate what the concentrations of different chemicals are in each census block. Although emissions were likely lower than usual in 2020 because of the COVID-19 shutdowns, we used 2020 data because it’s the most recent and most detailed available. (Prior to 2020, AirToxScreen provided results by census tract, each of which contains many blocks.) The data does not include the risk from formaldehyde in indoor air, which studies show is much higher than outdoors.
The data includes two categories of modeled chemical concentrations: ambient concentrations and exposure concentrations. Ambient concentrations are the agency’s estimates for the amount of a chemical in the outdoor air in the tract, whereas exposure concentrations are the agency’s estimates for how much of a chemical a human in the area realistically inhales.
We calculated incremental lifetime cancer risks by multiplying AirToxScreen’s exposure concentrations of formaldehyde by a figure called an Inhalation Unit Risk, which is the EPA’s best scientific estimate of how carcinogenic a chemical is. We used the new Inhalation Unit Risk for formaldehyde, which was finalized in August.
However, even the new IUR is an underestimate. It is based solely on the risk of nasopharyngeal cancer, which is rare. It does not reflect the risk of myeloid leukemia,