Toxicology and Poisoning Formaldehyde Formaldehyde (HCHO) CAS: 50-00-0; UN 1198 (Formalin), 2209 (Formalin) Synonyms of gaseous formaldehyde include formalin, formic aldehyde, methanal, methyl aldehyde, methylene oxide, oxomethane, and paraform. Victims exposed to only formaldehyde vapor do not pose a significant risk of secondary contamination; however, victims whose clothing or skin is contaminated with formalin can cause secondary contamination by direct contact or through off-gassing vapor. Formaldehyde is a highly toxic and flammable gas that is slightly heavier than air. It often is used in aqueous solution (formalin). Most formaldehyde exposures occur by inhalation or skin or eye contact. It is a potent allergen that can elicit hypersensitivity reactions in susceptible individuals. Description -- Formaldehyde is a nearly colorless gas with a pungent, irritating odor below 1 ppm. Its vapors are flammable and explosive. Because the pure gas tends to polymerize, it is used commonly in solution. Formalin is the aqueous solution of formaldehyde (37% to 50% formaldehyde), which contains up to 15% methanol as a stabilizer. Routes of Exposure -- Inhalation - Most formaldehyde exposures occur by inhalation or skin/eye contact. In cases of acute exposure, formaldehyde will most likely be detected by smell; however, persons who are sensitized to formaldehyde may experience headaches and minor eye and airway irritation at levels below the odor threshold. For them, odor is not a adequate indicator of formaldehyde's presence and may not provide reliable warning of dangerous concentrations. Odor adaptation does occur. Skin/Eye Contact - Formaldehyde vapor or formalin splashes can cause injury to the skin and eyes. Ingestion - Ingestion of as little as 30 mL of 37% formalin has been reported to cause death in an adult. Sources/Uses -- Formaldehyde is produced by the oxidation of methanol. It is among the 25 most abundantly used chemicals in the world. It is used in the manufacture of plastics, resins, and urea-formaldehyde foam insulation. Formaldehyde- containing resins are found in construction materials (plywood, particle board, and fiber board) and are used in the processing of paper, carpets, crease-resistant textiles, paint, and furniture. Under certain conditions, formaldehyde may be released from building materials, carpeting, furniture, drapes, etc., thereby contributing to indoor pollution. Formalin in varying concentrations is used as a disinfectant, antiseptic, deodorant, tissue preservative, and embalming fluid. Properties of Formaldehyde -- Appearance: Nearly colorless gas with a pungent, irritating odor Warning properties: Odor is detectable at less than 1 ppm, but many sensitive persons experience symptoms below the odor threshold. OSHA PEL (Permissible Exposure Limit) = 1 ppm (averaged over an 8-hour workshift) OSHA STEL (Short Term Exposure Limit) = 2 ppm (15-minute sample) NIOSH IDLH Immediately Dangerous to Life or Health = 30 ppm AIHA ERPG-2 = 10 ppm Molecular weight = 30.0 Boiling point (760 mm Hg) = -6 degrees F Vapor pressure (67 degrees F) = > 760 mm Hg Vapor density = 1.07 (air = 1) Miscible with water Flammable gas between 7% and 73% (concentration in air); combustible liquid (formalin) Health Effects Formaldehyde is an eye, skin, and respiratory tract irritant. When inhaled, it can produce bronchospasm and pulmonary edema. Metabolic acidosis may occur as a result of accumulation of the metabolite formic acid in the body. Formaldehyde is a potent sensitizer and a suspected human carcinogen. Acute Exposure -- In high concentrations, formaldehyde reacts with most substances within the cell, thus interfering with cellular functions. In exposed tissue, it causes precipitation of proteins, which results in coagulation necrosis. Because formaldehyde is highly water soluble, it produces immediate local irritation in mucous membranes including eyes, nose, and upper respiratory tract. Formaldehyde is metabolized to formic acid, which may accumulate in the body and cause metabolic acidosis. Respiratory - Even fairly low concentrations of formaldehyde can produce rapid onset of nose and throat irritation, which cause coughing, chest pain, dyspnea, and wheezing. Higher exposures can cause significant inflammation of the lower respiratory tract resulting in laryngeal spasm and edema, tracheobronchitis, bronchospasm, pneumonitis, and pulmonary edema. Pulmonary injury may evolve over 12 hours or more. Previously sensitized individuals can develop severe bronchospasm at very low concentrations (0.3 ppm). Attacks may begin immediately or can be delayed for 3 to 4 hours; effects may worsen for up to 20 hours after exposure and can persist for several days. Metabolic - Accumulation of the formic acid metabolite can cause an anion gap metabolic acidosis. If formalin is ingested, the absorption of methanol stabilizer may contribute to metabolic acidosis and can result in both an anion and osmolar gap. Immunologic - In persons who have been previously sensitized, inhalation and skin contact may result in contact dermatitis, urticaria, anaphylactic reactions, and rarely, hemolysis. Gastrointestinal - Ingestion of aqueous solutions of formaldehyde may cause severe corrosive esophageal and gastric injury. Nausea, vomiting, diarrhea, abdominal pain, gastritis, ulceration, and perforation can occur. Both formaldehyde and the ethanol stabilizer are easily absorbed and can contribute to systemic toxicity. Aspiration of stomach contents containing formalin may cause pneumonitis. Ocular - Exposure to low vapor concentrations can cause eye irritation that abates within minutes after exposure has ended. Exposure to high vapor concentrations or formalin splashed in the eyes can lead to corneal ulceration or opacification, corneal necrosis, perforation, and acute glaucoma. These effects may be delayed for 12 hours or more. Dermal - Exposure to vapor concentrations greater than 300 ppm or to formalin solutions can cause irritation and skin burns. In sensitized persons, contact dermatitis may develop at air levels less than 1 ppm. Potential Sequelae - Pulmonary function in survivors of severe inhalation injury usually returns to normal. Eye exposure to high concentrations of formaldehyde or formalin can cause ulceration and perforation of the cornea, eventually resulting in blindness. Esophageal strictures can occur after ingestion. Chronic Exposure -- The major concerns of repeated formaldehyde exposure are sensitization and cancer. In sensitized persons, formaldehyde can cause asthma and contact dermatitis. In persons who are not sensitized, prolonged inhalation of formaldehyde at low levels is unlikely to result in chronic pulmonary injury. Formaldehyde is listed by IARC and NTP as a substance that may reasonably be anticipated to be a carcinogen. Various studies suggest that long-term formaldehyde exposure is associated with increased risk in humans of nasal, mouth, throat and lung cancer, leukemia, and brain cancer. Evidence suggests that formaldehyde does not cause adverse reproductive or developmental effects. Formaldehyde does not appear in a 1991 report published by the US General Accounting Office (GAO) which lists 30 chemicals of concern because of their reproductive and developmental consequences. TERIS states that the teratogenic risk to a child born after exposure during gestation is none to minimal. Shepard's Catalog of Teratogenic Agents indicates that there is no evidence that formaldehyde is embryotoxic in humans. Prehospital Management Inhalation of formaldehyde can cause airway irritation, bronchospasm, and pulmonary edema. Formaldehyde absorption can cause severe systemic toxicity leading to metabolic acidosis and coma. There is no specific antidote for formaldehyde poisoning. Treatment consists of supportive measures. Potential for Secondary Contamination. Victims exposed to only formaldehyde gas do not pose a significant risk of secondary contamination to personnel outside the Hot Zone. However, victims whose clothing or skin is contaminated with formaldehyde-containing solution (formalin) can secondarily contaminate personnel by direct contact or through off-gassing vapor. Hot Zone -- Rescuers should be trained and appropriately attired before entering the Hot Zone. If the proper equipment is not available, or if rescuers have not been trained to use it, call for assistance from a local or regional hazmat team or other properly equipped response organization. Rescuer Protection - Rescuers in the Hot Zone should wear self-contained breathing apparatus (SCBA). Chemical-protective clothing and gloves are required if contact with concentrated formaldehyde vapor or formalin is possible. ABCs - Quickly establish a patent airway. Stabilize the cervical spine with a collar if trauma is suspected. Administer supplemental oxygen and assist ventilation with a bag-valve-mask device if necessary. Victim Removal - If victims can walk, lead them out of the Hot Zone to the Decontamination Zone. If a victim is unable to walk, remove him or her on a backboard or gurney. If there is no means of transport, carefully drag the victim out. Decontamination Zone -- Victims with exposure to only formaldehyde vapor and with no skin or eye irritation do not need decontamination. They may be transferred immediately to the Support Zone. For all others see Basic Decontamination on the following page. Rescuer Protection - Rescuers in the decontamination zone should wear self-contained breathing apparatus (SCBA) and chemical-protective clothing and gloves if they will be caring for victims with formalin-soaked clothing or skin. If the proper equipment is not available, or if rescuers have not been trained to use it, call for assistance from a local or regional hazmat team or other properly equipped response organization. If the decontamination area is outdoors and has good natural ventilation, a lesser level of respiratory protection may suffice. ABCs - Quickly establish a patent airway. Stabilize the cervical spine with a collar if trauma is suspected. Supplemental oxygen can be administered if available. Evaluate the need for an intravenous line, cardiac monitor, and life support. Basic Decontamination- Remove and double-bag contaminated clothing. Patients who are able and cooperative may remove their own clothing and assist with basic decontamination. Flush liquid-exposed skin and hair with plain water for at least 5 minutes. Flush exposed or irritated eyes with plain water or saline for 3 to 5 minutes. Remove contact lenses if present. In case of formalin ingestion, do not induce emesis. The effectiveness of activated charcoal is unknown. Administer 1 to 2 glasses of water to dilute stomach contents if the patient is conscious and able to swallow. Transfer to Support Zone - As soon as basic decontamination is completed, move the patient to the Support Zone. Support Zone -- Be certain that patients have undergone basic decontamination (see Decontamination Zone above). Patients who have undergone proper decontamination or who have been exposed to only vapor pose no serious risk of causing secondary contamination. Support Zone personnel require no specialized protective gear in such cases. ABCs - Quickly establish a patent airway. Stabilize the cervical spine with a collar if trauma is suspected. Watch for signs of airway swelling and obstruction such as progressive hoarseness, stridor, or cyanosis. Administer supplemental oxygen and assist ventilation with a bag-valve-mask device if necessary. Evaluate the need for an intravenous line, cardiac monitor, and life support. Advanced Treatment - Treat bronchospasm with aerosolized bronchodilators. Intubate the trachea if indicated (severe respiratory distress or apnea). When endotracheal intubation cannot be performed due to airway obstruction, perform cricothyroidotomy if equipped and trained to do so. Additional Decontamination - If skin or eyes remain irritated, continue rinsing with water or saline. Remove contact lenses if present and irrigate the eyes with saline via IV tubing for 10 to 15 minutes or until pain and irritation have resolved. In case of formalin ingestion, do not induce emesis. Administer 1 to 2 glasses of water to dilute stomach contents if it has not been administered in the decontamination zone and if the patient is conscious and able to swallow. Transport to Medical Facility - Report to the base station and receiving medical facility the condition of the patient, treatment given, and estimated time of arrival at the medical facility. If a patient has ingested formalin, prepare the ambulance for possible vomiting of toxic material. Have ready several towels and opened plastic bags to quickly isolate and clean up vomitus. Multi-Casualty Triage -- If possible, consult with the base station physician or regional poison control center for advice regarding triage of multiple victims. Patients who have ingested formalin or have obvious injury, such as severe wheezing or dyspnea, or skin or eye burns, should be transported immediately to a medical facility. Patients with no eye, skin, or throat irritation, or with only mild or transient symptoms, probably did not have a significant exposure and probably will not develop severe complications. After recording their names, addresses, and telephone numbers, they may be released from the scene with instructions to rest and to seek medical care if they develop respiratory difficulty. (See the follow-up instructions on the reverse side of Formaldehyde--Patient Information Sheet.) Emergency Department Management Inhalation of formaldehyde can cause airway irritation, bronchospasm, and pulmonary edema. Formaldehyde absorption can cause severe systemic toxicity leading to metabolic acidosis and coma. There is no specific antidote for formaldehyde poisoning. Treatment consists of supportive measures. Potential for Secondary Contamination -- Hospital personnel in an enclosed area can be secondarily contaminated by vapors off-gassing from heavily soaked clothing. Patients do not pose a contamination risk after contaminated clothing is removed and the skin is washed. Decontamination Area -- Patients with exposure to only formaldehyde vapor and with no skin or eye irritation do not need decontamination. They can be transferred immediately to the Critical Care Area. Other patients will require decontamination as described below. ABCs - Evaluate and support airway, breathing, and circulation. Watch for signs of airway compromise. Monitor cardiac rhythm. Treat bronchospasm with aerosolized bronchodilators. Basic Decontamination - If the patient has not been decontaminated, perform the decontamination procedure immediately. Patients exposed to only vapor do not require decontamination unless they have skin or eye irritation. Since touching clothing or skin wet with formalin may cause bums, ED staff should don chemical-resistant jumpsuits (e.g., Tyvek, Saranex) or butyl rubber aprons, rubber gloves, and eye protection. After the patient has been decontaminated, no special protective clothing or equipment is required for ED personnel. If the patient's clothing is wet with formalin, quickly remove and double-bag the contaminated clothing and all personal belongings while flushing the skin. Flush exposed skin with copious water (preferably under a shower). Remove contact lenses and irrigate exposed eyes with water for at least 15 to 30 minutes. An ophthalmic anesthetic, such as 0.5% tetracaine, may be necessary to alleviate blepharospasm, and lid retractors may be required to allow adequate irrigation under the eyelids. Critical Care Area -- Be certain that appropriate decontamination has been carried out. See Basic Decontamination on the preceding page. ABCs - Evaluate and support may, breathing, and circulation. Watch for airway compromise. Continuously monitor cardiac rhythm. Treat hypotension, seizures, and ventricular arrhythmias in the conventional manner. Patients with significant and persistent CNS depression should be evaluated for the presence of intercurrent disorders (e.g., trauma, hypoglycemia, and drug intoxication). Inhalation Exposure - Administer supplemental oxygen by mask to patents with respiratory complaints. Observe patents in respirator distress for up to 12 hours and periodically reexamine them using chest examinations and other appropriate studies. Follow-up as clinically indicated. Skin Exposure - If formalin or high concentrations of formaldehyde vapor were in contact with the skin, chemical bums may result Treat chemical bums as thermal bums. Eye Exposure - If eye irritation or injury is evident, test visual acuity and examine the eyes for corneal damage using a magnifying device or a slit lamp and fluorescein staining. Small corneal defects may be treated with topical ophthalmic antibiotic ointment or drops and analgesic medication. Immediately consult an ophthalmologist for patients with severe corneal injury. Ingestion - Do not induce emesis. If not administered previously, administer water or milk to dilute the formalin in the stomach and minimize corrosive injury. Perform gastric lavage if large amounts of formalin have been ingested and the ingestion has occurred within 30 to 60 minutes of presentation. The effectiveness of activated charcoal in binding formaldehyde is unknown. Consider endoscopy to evaluate the extent of corrosive injury to the gastrointestinal tract. Antidotes and Other Treatments - There is no antidote for formaldehyde poisoning. Hemodialysis is effective in removing formate and methanol and in correcting severe metabolic acidosis. Metabolic acidosis also can be treated with sodium bicarbonate. Correction of acidosis should be guided by ABGs. If methanol poisoning due to ingestion of formalin is suspected (serum methanol level of greater than 20 micrograms/dL or elevated osmolar gap), start ethanol infusion. With 10% ethanol, the loading dose is 7.5 mL/kg maintenance dose is 1 to 1.5 mL/kg/h; and maintenance dose during hemodialysis is 1.5 to 2.5 mL/kg/h. Laboratory Tests - Useful laboratory studies include CBC, electrolytes, BUN, creatinine, glucose, urinalysis (may see protein, casts, and red blood cells), liver function tests, osmolar gap, and ABGs (to monitor acidosis in severe toxicity). Chest radiography and ABGs may be helpful in cases of inhalation exposure. Plasma formaldehyde levels axe not useful. Disposition and Follow-up -- Hospitalization should be considered for patients with evidence of systemic toxicity from any route of exposure. Delayed Effects - Patients with a history of significant ingestion exposure should be admitted to an intensive care unit for observation (for aspiration pneumonia and renal failure). Patients with inhalation exposure who complain of chest pain, chest tightness, or cough should be observed and examined periodically for 6 to 12 hours to detect delayed onset pulmonary edema or respiratory failure. Patient Release - Patients who are asymptomatic should be observed for 4 to 6 hours, then discharged if no symptoms occur during this period. Advise discharged patients to seek medical care promptly if symptoms develop. (For a list of symptoms, see Formaldehyde--Patient Information Sheet.) Follow-up - Patients with eye injury requiring ophthalmic care should be reevaluated in 24 hours. Reporting -- If a work-related incident has occurred, you may be legally required to file a report; contact your state or local health department. Other persons may still be at risk in the setting where this incident occurred. OSHA may be contacted for assistance in evaluating workplace conditions, or an appropriate public agency can be notified if a public health risk exists. If appropriate, inform patients that they may request an evaluation of their workplace from the Hazard Evaluation Division at NIOSH. Formaldehyde Patient Information Sheet This handout provides information and follow-up instructions for persons who may have been exposed to formaldehyde gas or solution (formalin). What is formaldehyde? Formaldehyde is a nearly colorless, highly irritating gas with a sharp odor. It dissolves easily in water and is found in formalin (a formaldehyde solution containing water), formaldehyde, and methanol (wood alcohol). Formaldehyde is used in the manufacture of plastics, urea-formaldehyde foam insulation, and resins used to make construction materials, paper, carpets, textiles, paint, and furniture. What immediate health effects may result from formaldehyde exposure? Most people will notice the pungent odor and experience irritation of the eyes, nose, and throat when they breathe the gas, even at low levels for short periods. Longer exposure or higher doses can cause coughing or choking. Severe exposure can cause death from throat swelling or from chemical bums to the lungs. Direct skin contact with formaldehyde containing liquids, such as formalin, may cause bums. Eye exposure to concentrated gas or liquid can cause serious corneal bums. Drinking formalin can cause severe bums to the throat and stomach, and as little as 30 mL (about 2 tablespoons) of formalin can cause death. What is the treatment for formaldehyde poisoning? There is no antidote for formaldehyde poisoning, but its effects can be treated and most exposed persons do recover fully. Patients who have had a serious exposure (with signs and symptoms such as tearing eyes, running nose, or severe or persistent coughing) may require close medical observation for 18 hours or more. Are any future health effects likely to occur? After a single, small exposure, no delayed or long term effects are likely to occur. After a severe exposure, symptoms may be delayed up to 18 hours. The reverse side of this page lists some signs and symptoms to watch for--if any of them occur, seek medical care. Long-term, repeated exposure to formaldehyde in the workplace may cause cancer of the nasal passages, mouth, lungs, or bone marrow. What tests can be done if a person has been exposed to formaldehyde? There are no specific blood and urine tests that can indicate a recent exposure to formaldehyde. Generally, the severity of irritation symptoms is the best indicator of the seriousness of the exposure. Blood tests and a chest X ray may be done to evaluate possible lung injury. Where can more information about formaldehyde be found? More information about formaldehyde may be obtained from your regional poison control center;, your state, county, or local health department; the Agency for Toxic Substances and Disease Registry (ATSDR); your doctor;, or a clinic in your area that specializes in occupational and environmental health. If the exposure happened at work, you may wish to contact the Occupational Safety and Health Administration (OSHA) or the National Institute for Occupational Safety and Health (NIOSH). Ask the doctor who gave you this form for help in locating these telephone numbers. Formaldehyde Follow-up Instructions ( ) Call your doctor or the Emergency Department if you develop any of the following symptoms within the next 24 hours: * cough * difficulty breathing or shortness of breath * chest pain * increased pain or discharge from your eyes * increased redness, pain, or pus-like discharge in the area of a skin burn * fever * unexplained drowsiness, fatigue, headache * belly pain, vomiting, diarrhea ( ) No follow-up appointment is necessary unless you develop any of the symptoms described above. ( ) Call for an appointment with Dr. _________ in the practice of_________. When you call for your appointment, please tell the receptionist/nurse that you were treated in the Emergency Department at__________________ Hospital by __________ and were advised to be seen again in __ days. ( ) Return to the Emergency Department/__________Clinic on (date)__________ at____ AM/PM for a follow-up examination. ( ) Do not perform vigorous physical activities for __ days. ( ) You may resume everyday activities including driving and operating machinery. ( ) Do not return to work for __ days. ( ) You may return to work on a limited basis. See instructions below. ( ) Avoid exposure to cigarette smoke for 24 hours since smoke may worsen injury to your lungs. ( ) Avoid drinking alcoholic beverages or taking aspirin for 24 hours since these substances may aggravate injury to your stomach lining or may have other effects. ( ) You may continue taking the following medication(s) that your doctor(s) prescribed for you:____________________________________________________ _______________________________________________________________________ ( ) Other instructions:____________________________________________________ _______________________________________________________________________ Signature of patient _______________________ Date _________________________ Signature of physician _____________________ Date _________________________ Above courtesy of C.D.C.