by Topher Sanders, with additional reporting by Sharon Lerner and Al Shaw

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The air was packed with savory and sweet aromas when I walked into my colleague’s Brooklyn apartment for dinner. The sizzle and pop of rice and green beans cooking on the gas stove blended with soft jazz coming from the TV. Candle flames danced and flickered.

But we weren’t gathering just to enjoy a late-summer meal. We were trying to expose an uninvited yet ever-present guest — formaldehyde.

The invisible chemical can be harmless in small amounts, but in larger concentrations, it can cause headaches, dizziness, respiratory illness and asthma. It is also responsible for more cancer than any other toxic air pollutant.

Because of its importance to many industries, formaldehyde has proven difficult to regulate. This year, President Joe Biden’s administration finally appeared to make some progress, though it was modest. If the past is any guide, however, even those limited efforts are likely to hit a dead end after Donald Trump is inaugurated. Knowing our risks is essential to protecting ourselves, experts say. Last week, ProPublica published a tool to show how much formaldehyde is in the outside air.

But our biggest exposure happens indoors, so my colleagues and I set out to do our own testing.

We read thousands of pages of scientific studies and Environmental Protection Agency documents on the dangers of formaldehyde, and we learned the toxic chemical is nearly impossible to escape. Formaldehyde is in furniture and flooring. It is in the adhesives used in wallpaper and carpets. It’s given off by candles, fireplaces and gas stoves. And it’s in hair products and cosmetics.

EPA scientists recently examined how low formaldehyde levels should be to ensure the chemical doesn’t trigger an allergic reaction, breathing problems or asthma symptoms, and the concentrations found inside the average home were far above that. Over a lifetime of exposure to the formaldehyde in an average home, a person’s risk of developing cancer is more than 250 times the risk level that the Clean Air Act sets as a goal. Even that number vastly underestimates the risk from cancer because the EPA did not factor in the chance of developing myeloid leukemia, the most common cancer caused by the chemical.

“It is everywhere, it is in everything,” University of California, Los Angeles researcher Nicholas Shapiro told me. Shapiro, who has spent years studying formaldehyde exposure, is working on a book, “Homesick,” that explores how formaldehyde, among other toxic chemicals in our homes, poses a danger to our health. “It is holding together our built environment and also chemically corroding us at the same time. It’s part of the fundamental paradox of the world that we’ve built, where this chemical is holding together our homes. We have built our society around it.”

My colleague Sharon Lerner and I traveled around New York City and New Jersey for weeks with equipment to measure the chemical’s presence.

The results proved concerning.

Sharon and I took a moment to wipe the July sweat from our brows as we got our testing equipment ready in a sprawling shopping center in Brooklyn. I placed a pump about the size of a large tape measure into Sharon’s backpack. The pump pulled in air through a two-foot rubber hose that extended out of the backpack’s main compartment.

I turned on the pump, which made a soft pneumatic sound. We were ready to ride the escalator up to an Ashley Furniture showroom in the Industry City mall.

“Can I help you guys find something?” a friendly salesperson asked.

“We’re just looking, thanks,” I replied.

We hoped the hose sticking out of Sharon’s backpack and the sound of the pump wouldn’t lead to more questions. For the next 20 minutes, we perused the showroom, opening cabinets, dressers and nightstands.

The store offers a wide range of budget furniture that can be made with foams, adhesives and wood composites that contain formaldehyde. These products go through a process called off-gassing, where chemicals they contain are released into the air over time. New furniture right out of the box has been shown to off-gas more than pieces that have been sitting out of their packaging for a while.

[Formaldehyde] is holding together our built environment and also chemically corroding us at the........

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