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Navigating and Controlling the Hazards of Formaldehyde

Although ubiquitous, formaldehyde is one of the most hazardous chemicals used today

Vince McLeod, CIH

Vince McLeod is an American Board of Industrial Hygiene-certified industrial hygienist and the senior industrial hygienist with Ascend Environmental + Health Hygiene LLC in Winter Garden, Florida. He has more...

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Formaldehyde is widely used in many everyday products like hair-straightening products and other cosmetics, as well as manufactured wood products such as flooring and furniture. It is also one of the most-used chemicals in research laboratories, where we encounter it in everything from tissue fixation to benchtop perfusions to instrument sterilization and use it to preserve everything from cell cultures to whole-organ specimens. Therefore, potential exposures can come from many sources.

This is important because improper or careless use can cause serious health problems. Read on to get a closer look at the hazards of formaldehyde and how to safely use this common sterilizer and preservative.

The use of pure formaldehyde is uncommon. In laboratories, it is typically used in an aqueous solution known as formalin, which contains 37 percent formaldehyde. Formalin is also oftentimes mixed with other chemicals to make embalming fluids or preserving solutions.

Acute health effects

Let us take a look at the physical and chemical properties and the acute (short-term, immediate) health effects.1 Formaldehyde is a flammable, colorless gas with a pungent, suffocating odor due to its extreme reactivity. It is classed as both a powerful irritant and sensitizer and is intensely irritating to mucous membranes. Its presence is easily felt even in concentrations well below one part per million (ppm). Published studies have also shown the odor threshold to be well below one ppm.2,3 It is first felt in the eyes, nose, and throat as tingling and then irritation. Concentrations above five ppm are not tolerated by most individuals, with severe tearing in the eyes as well as coughing and irritation of the upper respiratory tract resulting from exposure.

It is important to note that formaldehyde is also a sensitizer. This means that even with continued exposure to low-level concentrations, the senses become fatigued and the chemical’s numbing effect takes over with the irritating effects gradually subsiding. Unfortunately, we have encountered employees—not wanting to be labeled complainers—who tell us they just “tough it out” for a few minutes and the feeling goes away. They simply do not understand that they are still being exposed.

Formaldehyde is also a skin irritant and may cause dermatitis and possible allergic reactions from repeated exposures due to skin sensitization. Vapors or solutions may cause pain, white discoloration, roughness, and burns. In exposed individuals, subsequent exposures may result in a sensitization dermatitis characterized by the sudden eruption of blisters on the eyelids, face, neck, scrotum, and arms. Prolonged or repeated exposures may cause burns, numbness, itching rash, fingernail damage, hardening or tanning of the skin, and sensitization. Absorption through the skin also adds to the total exposure.

Possible severe chronic harm?

Potentially serious health effects can result from chronic (long-term) formaldehyde exposure. Where the mucous membrane and skin effects are largely reversible upon removal from the exposure, formaldehyde can cause chronic biological effects. These range from central nervous system depression to kidney and liver damage, reproductive and fetal effects, and cancers. Repeated or prolonged low-level exposure may cause respiratory impairment, kidney injury, and pulmonary sensitization. Neuropsychological effects may include sleep disorders, irritability, altered sense of balance, memory deficits, loss of concentration, and mood alterations. Menstrual disorders and secondary sterility have occurred in women.

Related Article: Preserving, Anyone?

Formaldehyde is now listed by the International Agency for Research on Cancer (IARC), the National Toxicology Program (NTP), and others as a known human carcinogen.4 However, the EPA still considers formaldehyde a probable human carcinogen (cancer-causing agent) and has ranked it in the EPA’s Group B1. Long-term exposure may increase the risk of upper respiratory-tract cancers, including those of the nasal cavity and sinuses, and possibly leukemia.

Exposure prevention

Begin by determining where and how formaldehyde is used in your facility. Inspect all use areas while activities are ongoing. Note any odors. Interview employees on their procedures. Note the type of formaldehyde products used.

The Safety Guys recommend consulting the OSHA formaldehyde standard, 29CFR1910.1048, for regulatory requirements and guidance.3 This standard covers all occupational exposures to formaldehyde, including gas, solutions, and any materials that release formaldehyde.

First you must determine employee exposures by conducting appropriate monitoring. If in-house capability is not available, a competent industrial hygienist or similar professional can handle the job. OSHA has established an action level of 0.5 ppm and a permissible exposure limit (PEL) of 0.75 ppm, both based on eight-hour time-weighted averages (TWA). There is also a short-term exposure limit (STEL) of 2.0 ppm, a 15-minute average that employees shall never exceed. Periodic monitoring must be conducted every six months for employees exposed at or above the action level.

Review monitoring results and ensure employees potentially exposed above the limits are placed in a medical surveillance program. Collect initial medical history information and perform a baseline physical. OSHA provides considerable guidance in the rule appendices and on their website.

Safety and health training is essential for all employees falling under this standard. Training should focus on the signs and symptoms of exposure, the possible health effects of formaldehyde exposure, proper personal protective equipment, medical surveillance, monitoring, exposure controls, and first aid.


The best and most essential exposure control is properly designed and adequately maintained engineering systems (e.g., ventilation). We have all experienced facility spaces changing uses over time. We find anatomy labs in what was office space, or surgeries performed out on the benchtop without any exhaust. That is why it is important to review ventilation in all formaldehyde use areas and ensure adequate exhaust and proper design. Attempt to capture vapors as close to the source as possible through use of snorkel exhaust or fume hoods. And, most importantly, make sure formaldehyde use areas are on dedicated singlepass ventilation systems.

Our number-one goal is protecting our employees and providing a safe workplace. Formaldehyde, essential to successful research in many applications, is potentially hazardous and, if used carelessly, can produce serious harm. But with careful planning, safe procedures, personal protective equipment, and exposure controls, we can use formaldehyde safely and protect employees.


1. Formaldehyde. Material Safety Data Sheet. Fisher Scientific, Inc. Fair Lawn, NJ. September 2010, 

2. Medical Management Guidelines for Formaldehyde. Agency for Toxic Substances and Disease Registry. Atlanta, GA. September 2010,

3. Formaldehyde. Occupational Safety and Health Administration. Washington, DC. December 2008, 

4. Formaldehyde and Cancer Risk. National Cancer Institute, National Institute of Health. Bethesda, MD. June 2011, .