Formalin technical guidelines

Uninhibited formalin is a solution that is about 37% formaldehyde and 63% water, and that concentration makes it a highly irritating and potentially carcinogenic liquid that requires controls. See the Substance Identification in 1910.1048 App A for the exact composition and hazard notes.

• The 37% concentration means formalin is a strong irritant to eyes, skin and airways and can form corrosive decomposition products like formic acid when heated.
• Inhibited solutions may contain methanol as a stabilizer; uninhibited (the guideline subject) does not. Employers should modify training to reflect the exact material used and any impurities that might be present. See 1910.1048 App A.

OSHA's exposure limits for formaldehyde are a TWA of 0.75 ppm and a STEL of 2 ppm. This means average exposure over an 8-hour shift must not exceed 0.75 ppm and any 15-minute period must not exceed 2 ppm. See the Exposure Limits in 1910.1048 App A.

• There is also an action level of 0.5 ppm that triggers monitoring and medical surveillance requirements described in the standard.

No — workers should not rely on smell or irritation because people can adapt and become less sensitive, which can lead to overexposure. The guideline warns that odor and eye-irritation perception decreases with time, so biological warning signs are unreliable. See the note in 1910.1048 App A.

• Use monitoring and engineering controls rather than personal sensation to detect hazard levels.

An employer must monitor employee exposure if it may exceed the 0.5 ppm action level as an 8-hour TWA or the 2 ppm STEL. See the Monitoring Requirements in 1910.1048 App A.

• Employers may identify a single “high-exposure” employee to represent similar exposures rather than sampling everyone.
• If representative monitoring is used, that employee wears a sampling device while performing normal duties.

OSHA accepts passive diffusion badges, sorbent tubes with pumps, impingers, and direct-reading instruments as appropriate methods so long as they accurately evaluate breathing-zone concentrations. See Monitoring Techniques in 1910.1048 App A.

• For TWA (8-hour) evaluations, full-shift samples from the employee's breathing zone are preferred.
• For STEL compliance, take multiple 15-minute short-term samples to identify peak exposures.
• Employers must choose validated sampling and analysis methods that are accurate for the conditions encountered.

Air samples for exposure evaluation must be taken from the employee's breathing zone so they represent the air the employee actually inhales. See Evaluation of 8-hour Exposure in 1910.1048 App A.

• For TWA compliance, collect samples that cover the full shift; for short-term tasks, collect the appropriate 15-minute samples in the breathing zone during those tasks.

A representative employee is one who performs the job that likely has the highest exposure and wears the sampling device to represent similar exposures for the group. The employee should perform their normal work while wearing the monitor and report any problems with the device to the monitorer. See Monitoring Requirements in 1910.1048 App A.

• The employer must choose someone who spends the most time near the process or source of formaldehyde.

Your employer must inform you of monitoring results that are representative of your job, and posting the results where you have ready access satisfies this requirement. See Notification of Results in 1910.1048 App A.

• Results may be given in writing or by posting, and must be made available in a way employees can readily review them.

Medical surveillance must be offered at no cost and at a reasonable time and place if you are exposed above 0.5 ppm TWA or 2 ppm STEL; it is offered at assignment and annually while exposure remains at or above those levels. See Medical Surveillance in 1910.1048 App A.

• The surveillance includes a medical-disease questionnaire and, if the physician finds it necessary, a physical examination.
• If you are required to wear a respirator, the employer must offer a physical exam and pulmonary function test annually.
• The physician provides a written opinion to the employer and must tell you about any medical conditions that would be aggravated by formaldehyde exposure.

Immediate first aid is: for inhalation, remove the person to fresh air and get medical help if symptoms persist; for skin contact, remove contaminated clothing and wash the area for 15–20 minutes; for eye contact, flush eyes for 15–20 minutes and seek medical attention. See Emergency and First Aid Procedures in 1910.1048 App A.

• For severe inhalation with respiratory distress, rescuers must use appropriate respiratory protection (e.g., SCBA) before entering the area.
• If ingestion occurs and the victim is conscious, administer milk, water, or activated charcoal and get immediate medical attention.

You must enter a formaldehyde IDLH atmosphere (about 100 ppm or more) only with full-body protection and either a positive-pressure self-contained breathing apparatus (SCBA) with full facepiece or a supplied-air respirator with a full facepiece operated in positive pressure. See Entry Into an IDLH Atmosphere in 1910.1048 App A.

• These devices are required because of the immediate danger to life and health at such concentrations.

Negative-pressure full facepiece respirators with approved cartridges may be used within their limitations, but cartridges typically cannot be used for a full workshift for formaldehyde; when used, employers must provide fit testing at least annually. See Protective Equipment—Respiratory Protection in 1910.1048 App A.

• For exposures above cartridge limits or in IDLH conditions, employers must provide positive-pressure respirators (e.g., SCBA or positive-pressure supplied air).
• Employers are responsible for selecting the appropriate respirator based on monitoring data and respirator limitations.

When handling formalin solutions of 1% or more, employees must have material impervious gloves, eye protection (goggles), and face protection (face shield if risk of splash to face) provided by the employer at no cost. See Protective Equipment and Clothing in 1910.1048 App A.

• Employers should select gloves using permeation testing and follow ACGIH guidelines.
• Whole-body impervious clothing is required to prevent repeated or prolonged skin contact; if special clothing is required, employers must provide change rooms.

Employers should select protective gloves based on permeation testing results and in accordance with the ACGIH Guidelines for Selection of Chemical Protective Clothing. See the glove guidance in 1910.1048 App A.

• Selection must consider glove material compatibility with formaldehyde, expected contact duration, and potential degradation; employers must provide the gloves at no cost.

Ventilation is the primary engineering control: use local exhaust to capture formaldehyde at the source and general dilution ventilation when sources are spread out; coupled with safe work practices, these controls limit exposures. See Engineering Controls in 1910.1048 App A.

• Local exhaust must draw contaminants toward the hood inlet and away from workers.
• General ventilation effectiveness depends on air changes per hour.
• Administrative and work-practice controls (e.g., limiting time near the source) complement ventilation.

Formalin (37%) is a moderate fire and explosion hazard: its flash point is about 185 °F (85 °C), and its flammable vapor range in air is very wide (7%–73% by volume), so vapors can form explosive mixtures; cool containers and use appropriate extinguishing media. See Fire and Explosion Hazard in 1910.1048 App A.

• Use dry chemical, alcohol foam, CO2 or large-volume water fog; cool fire-exposed containers with water.
• Avoid sources of ignition and be aware that reaction with certain compounds yields explosive products.

Formaldehyde is incompatible with strong oxidizers, caustics, strong alkalies, isocyanates, anhydrides, and inorganic acids; with hydrochloric acid it can form bis-chloromethyl ether, a potent carcinogen, and reactions with certain compounds can form explosive products. See the Reactivity section in 1910.1048 App A.

• Employers must store and handle formaldehyde away from incompatible chemicals and design emergency procedures accordingly.

For small spills, place leaking containers in a ventilated area, absorb with inert material, and place waste in labeled containers for disposal; larger spills should be diked and possibly neutralized with sodium hydroxide or sodium sulfite. Spills greater than 1,000 lb/day are reportable under EPA Superfund rules. See Spill, Leak, and Disposal Procedures in 1910.1048 App A.

• Employers must follow all applicable local, state and federal hazardous-waste rules and notify authorities when required.

Employers must have written emergency procedures, train employees in their duties, make emergency equipment accessible and ensure contaminated equipment is cleaned before reuse; employees should evacuate unless assigned specific, trained emergency duties. See Emergency Procedures in 1910.1048 App A.

• Designated personnel may stop leaks and isolate hazards only if it can be done without risk; use water spray to reduce vapors and deny entry to the hazard area except for protected, trained responders.

If splashed, use emergency showers and eyewash stations immediately, remove contaminated clothing, and wash affected skin for at least 15–20 minutes; seek medical attention for significant irritation or burns. See Emergency and First Aid Procedures and Protective Equipment in 1910.1048 App A.

• Employers must provide these facilities and ensure workers know their location and proper use.

All records from medical examinations and disease surveys must be retained at the employer's expense; the physician provides a written opinion to the employer including recommended protective measures and restrictions. See Medical Surveillance in 1910.1048 App A.

• The physician must also inform the employee of any medical conditions that would be aggravated by formaldehyde exposure.

Material impervious protective clothing is required when employees handle formaldehyde solutions of 1% or more, and the employer must provide this clothing and equipment at no cost to employees. See Protective Equipment and Clothing in 1910.1048 App A.

• Employers must also provide facilities for changing and storage if whole‑body protective clothing is required.

Employers should train workers about the specific hazards of the formaldehyde-containing material they use, including physical and health hazards, exposure limits, monitoring results, emergency procedures, PPE use, and medical surveillance rights. See the opening and training guidance in 1910.1048 App A.

• Training should be tailored to the actual material and tasks employees perform and must cover emergency response, safe work practices, and how to use and maintain protective equipment.

Employers must measure short, high‑intensity tasks with 15‑minute samples and take several samples if needed to identify peak exposures to assure compliance with the 2‑ppm STEL. See Short-term Exposure Evaluation in 1910.1048 App A.

• Use appropriate short-term sampling devices or direct-reading instruments to capture task peaks.

When formaldehyde exposure comes from resins, employers must include hazard information about the resin and any impurities or decomposition products that may be toxic as part of employee training and hazard communication. See the guidance on resins in 1910.1048 App A.

• Evaluate exposures from the whole material (resin plus released formaldehyde) and adjust monitoring, PPE and medical surveillance accordingly.