Public Lab Wiki documentation

Formaldehyde Exposure

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What is formaldehyde?

Formaldehyde is a Volatile Organic Compound (VOC). It's a colorless, flammable gas with a distinct odor -- it's a major component in "new car smell." The chemical formula for formaldehyde is HCHO.


What are common sources of formaldehyde in the home?

  • wood floor finishes
  • pressed-wood products
  • wallpaper and paints
  • the combustion and oxidation of other hydrocarbons (including cigarettes, oil, natural gas, and emissions from laser printers and photocopiers).


How does formaldehyde come into contact with my body?

The formaldehyde from the products listed above can off-gas into the surrounding environment and be inhaled. Formaldehyde is very reactive, so reactive it doesn't travel very far into the body: if it's present in liquid or air and comes in contact with the body, it will react with the first body surface it comes in contact with -- mucus membranes, mostly, causing lung irritation, throat irritation, eye irritation and chemical sensitization (when people are exposed to industrial chemicals and become sensitive to them).

Is formaldehyde regulated in indoor environments?

  • Household formaldehyde exposure is not regulated in the United States.
  • Workplace formaldehyde exposure is regulated in the United States, but federal regulations diverge from federal science regarding what safe exposure limits are. More on this below.

In what units is formaldehyde measured?

Formaldehyde concentrations in the air are measured in parts per million (ppm) or parts per billion (ppb). The Kitagawa tubes used in the DIY Formaldehyde Test Kit are in ppm, check it out:


Here's a handy expression for mentally moving between parts per million and parts per billion:

0.01ppm = 10 ppb

Who is studying the effects of formaldehyde on human health?

The United States Federal Government:


The US National Toxicology Program -- part of the U.S. Department of Health and Human Services -- describes formaldehyde as "known to be a human carcinogen" ( See the PDF "Review of the Formaldehyde Assessment in the National Toxicology Program 12th Report on Carcinogens"



The US Agency for Toxic Substances and Disease Registry (ATSDR) -- part of the Center for Disease Control -- maintains toxicological profiles for a number of substances, including formaldehyde. ATDSR has published Minimum Risk Levels (MRL) (the level below which there are no expected health effects) for formaldehyde:

  • 0.04 ppm (acute);
  • 0.03 ppm (intermediate);
  • 0.008 ppm (8 ppb) (chronic)

But wait, what does a ATSDR Minimum Risk Level (MRL) mean?

"ATSDR uses the no observed adverse effect level/uncertainty factor (NOAEL/UF) approach to derive MRLs for hazardous substances. They are set below levels that, based on current information, might cause adverse health effects in the people most sensitive to such substance-induced effects. MRLs are derived for acute (1 14 days), intermediate (>14 364 days), and chronic (365 days and longer) exposure durations, and for the oral and inhalation routes of exposure. Currently MRLs for the dermal route of exposure are not derived because ATSDR has not yet identified a method suitable for this route of exposure. MRLs are generally based on the most sensitive substance-induced end point considered to be of relevance to humans. ATSDR does not use serious health effects (such as irreparable damage to the liver or kidneys, or birth defects) as a basis for establishing MRLs. Exposure to a level above the MRL does not mean that adverse health effects will occur.”

ATSDR has also created a list of Formaldehyde Regulations and Advisories for Air, Water, Food and other:

Scroll down to see chart (Figure 1) summarizing the scientific evidence on the health effects of varying concentrations of formaldehyde exposure as most recently updated by ATSDR in 2010.


The Occupational Safety and Health Administration (OSHA) workplace standard for "non-irritating" is (0.1ppm) [source: OSHA 1910.1048(l)] and is an order of magnitude higher than airborne formaldehyde concentrations that have the potential to pose a chronic exposure risk (.008ppm) [source: ATDSR MRL]. The concentration at which OSHA can take regulatory action against a company (0.5ppm) is an order of magnitude higher than the minimum risk level for acute exposure (.04ppm) [source: ATDSR MRL]. Unfortunately, OSHA standards are based upon methods that are available only behind a paywall, inhibiting their accessibility by the public: specifically, the American National Standards Institute / Hardwood Plywood and Veneer Association (ANSI/HPVA HP-1-2009) standard.


The Consumer Product Safety Commission does not specify irritating formaldehyde levels, indicating only that levels in buildings with formaldehyde containing products may be higher than 0.03 ppm, and recommends homeowners purchase wood products meeting American National Standards Institute / Hardwood Plywood and Veneer Association (ANSI/HPVA HP-1-2009) standard. Unfortunately, this standard is not available without purchase.

The State of California:


The California Office of Environmental Hazards and Hazard Assessment (OEHHA) has published Reference Exposure Levels of 7ppb:


The California Air Resources Board (CARB) has issued a report, On page 210, VENTILATION AND INDOOR AIR QUALITY IN NEW HOMES, CALIFORNIA ENERGY COMMISSION 2009, CEC-500-2009-085:

  • 98% of the homes exceeded the Chronic and 8‐hour RELs of 9 μg/m3
  • 59% exceeded the ARB indoor air guideline of 33 μg/m3
  • 28% exceeded the OEHHA Acute REL of 55 μg/m3

Here's a quote from CARB:

"By current estimates, 98 percent of new homes have indoor formaldehyde levels greater than 7ppb for the first 2-5 years. These are levels capable of inducing asthma-like respiratory symptoms."


What does it feel like to have formaldehyde in your indoor air?


Participants in the Where We Breathe study are most likely to be exposed at lower levels described in this chart (up to 0.6 ppm, or 600 ppb). This summary suggests that there is strong scientific evidence for formaldehyde having a range of human health effects at these lower levels of exposure: nasal and eye irritation, impaired short-term memory, change in pulmonary function, and exacerbation of asthma or allergies.


Figure 1. Existing evidence, health effects of breathing formaldehyde in humans and in animals. Reproduced from Addendum to the Toxicological Profile for Formaldehyde by the Agency for Toxic Substances and Disease Registry, 2010, p. 2.

To these symptoms on which scientific consensus already exists, we add a number of candidate symptoms observed at higher levels of formaldehyde exposure:

  • nausea
  • headaches
  • throat and skin irritation
  • cough
  • respiratory discomfort

...and also those symptoms reported to WWB investigator Nick Shapiro during his fieldwork with individuals living in FEMA-distributed trailers after Hurricane Katrina:

  • insomnia
  • nightmares
  • digestive trouble
  • changes in sense of smell or taste



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12.Wargocki, P., Wyon, D. P., Baik, Y. K., Clausen, G. & Fanger, P. O. Perceived air quality, sick building syndrome (SBS) symptoms and productivity in an office with two different pollution loads. Indoor air 9, 165–79 (1999).