List of toxic chemicals used in aircraft maintenance facilities 

1. Ammonia

Application: Surface and equipment cleaner. It is also widely used in fuel cells. 

Hazards: Fumes may irritate eyes. If inhaled, it can irritate the mouth, throat, nose, and lungs. 

Exposure limit: OSHA has determined an 8-hour time-weighted average (TWA) limit of 50 ppm (parts per million). 

Safe handling: Work in a well-ventilated location. Wear gloves, goggles, and a mask. Do not mix it with bleach; it causes poisonous fumes. 

First Aid: 

• Inhalation: Remove immediately fresh air. If breathing problems persist, get medical attention. 

• Skin/eye contact: Flush with water for 15 min. In case of serious exposure, it's necessary to get medical care. 

2. Acetone

Application: Cleaning equipment, degreasing, and removing adhesives or paint. 

Hazards: Flammable to a high degree. This chemical product can cause irritation on skin. One may also face dizziness and breathing problems due to exposure.

Exposure limit: OSHA establishes a limit of 1,000 ppm for an 8-hour shift. That's a lot, but acetone isn't highly hazardous in small concentrations. 

Handling: This must be used in an appropriately ventilated environment. Also, stay away from heat or open flame while working with it. Use gloves and eye protection. 

First aid: 

• Inhalation: Get fresh air. In case anyone feels dizziness, contact a doctor. 

• Skin contact: In case of skin contact, clean it with soap and water properly.  

• Ingestion: Do not provoke vomiting. Rather, look for medical treatment as soon as possible. 

3. Asbestos 

Use: It was once widely used for insulation and fireproofing, but its use is now prohibited. It is still used today in some aircraft brake linings and friction materials.   

Hazards: May cause cancer via inhalation. That's why long-term exposure can cause lung disorders. One may experience asbestosis and mesothelioma. 

Exposure limit: OSHA's permissible exposure limit (PEL) is 0.1 fibers per cubic centimeter of air averaged over an 8-hour work shift. This is a relatively modest figure, since even little doses of asbestos fiber are harmful. 

What the law really requires: This is where many facilities fail. OSHA's asbestos requirement (29 CFR 1910.1001) requires more than PPE for trained workers. If your facility has asbestos-containing brake linings or friction components, then you must: 

• Keep an eye on the air where asbestos work is going on 

• Develop a written exposure control plan  

• Conduct medical checks for workers working in "regulated areas," regions where asbestos may be beyond the permitted limit. 

• "We only have trained staff with PPE to handle it" does not fulfill this criterion. 

Safe handling: Do not disturb materials containing asbestos. Only trained workers wearing appropriate PPE and operating under a good exposure control plan should handle it.  

First aid:  

Inhalation: Remove from the area immediately; do not continue exposure. Get checked up for long-term consequences. 

4. Carbon monoxide (CO) 

Use: By-product of burning fuel in engines and heaters. 

Hazards: NIOSH has documented worker deaths from CO poisoning while in or around refueling vehicles. CO can potentially cause unconsciousness at high amounts. 

Exposure limits: OSHA has set a limit of 50 parts per million for an 8-hour shift. NIOSH has determined that 1,200 ppm is immediately hazardous to life and health. 

Handling: Ensure good ventilation in the work area. Get CO detectors. Never run engines in a closed space. 
 

First aid:  

• Inhalation: First, move to air as fast as possible and then look for medical help. Give oxygen if trained.  

5. Chlorofluorocarbon (CFC)

Use: Used for cleaning of metal and electronic parts. It is also found in minor amounts in aerosol propellants, coatings, and thermal stress testing. 

Hazards: Can induce dizziness and nausea. Also associated with long-term ozone depletion. 

Additional worker safety rule: CFCs used as refrigerants in aircraft ground equipment aren't merely an OSHA worry. Anyone who works with, recovers, or disposes of CFC refrigerants must have an EPA certification under Section 608 of the EPA's Clean Air Act. 

Safe handling: Use in areas with adequate ventilation and personal protective equipment. Do not inhale directly. 

First aid: 

• If inhaled: Move the person to fresh air. If you still have difficulties breathing, get medical attention. 

• Skin contact: Wash thoroughly with water. 

6) Ethylene glycol 

Use: Used mostly as a coolant and an aircraft de-icer. 

Hazards: Poisonous if ingested. Kidney damage, dizziness, and nausea may occur. NIOSH statistics show the ingestion hazard; even small amounts ingested can be harmful. 

Handling: Avoid contact with skin. Wear gloves & eye protection. Place it somewhere safe where it won't get in the way of others. 

First aid: 

• Inhalation: Remove to fresh air. 

• Ingestion: Get medical treatment immediately. Do not provide emetics. 

• Skin contact: Wash off with soap and water. 

7) Methylene chloride

This is the other chemical on this list with its own OSHA standard and is going through big regulatory change at present.

Use: In paint strippers, degreasers, and cleaning solutions. Also used as aerosol propellant.

Hazards: Listed as a carcinogen by OSHA and IARC. May induce dizziness, headache, and breathing problems if breathed.

OSHA requirements:

Methylene chloride has its own OSHA standard (29 CFR 1910.1052). Permissible exposure limits are 25 ppm as an 8-hour time-weighted average and 125 ppm as a short-term limit for 15 minutes. Exposure monitoring and medical surveillance are required for personnel handling the substance under the standard. This is not a broad industrial rule; it applies directly to aviation MRO work, and OSHA’s enforcement history for this standard expressly cites general aviation aircraft paint peeling as a covered activity.

Another level of regulation to be aware of:

In addition to OSHA, in 2024 the EPA published a final rule under the Toxic Substances Control Act that restricts most commercial and industrial uses of methylene chloride. A general compliance date is April 28, 2026. Uses in aviation and aerospace, such as paint and coating removal from safety-critical, corrosion-sensitive aircraft parts, have a time-limited exemption, but only if the facility implements a Workplace Chemical Protection Program (WCPP) as required by the EPA. If your facility uses methylene chloride to strip paint, you might need to check your WCPP status now.

Safe handling: Use a respirator, gloves, and safety clothes. Work in a ventilated space.

First aid: 

Inhalation: Get medical attention straight away. Move to fresh air.
Skin contact: Wash with plenty of water.

How to ensure chemical safety in aviation maintenance facilities 

The following is a review of the key stages to safe usage of chemicals in aviation repair shops. 

1) Safe packaging of chemicals  

• Store chemicals in well-ventilated areas. Shelving should be safe and temperature controlled and shielded from exposure and unwanted consequences. 

• Store chemicals according to compatibility. For example, keep oxidizers away from combustibles. 

• Keep the chemicals in containers that are properly labeled with hazard warnings, date of expiration, and instructions for handling.  

2) Proper use of personal protective equipment (PPE) 

• Use appropriate PPE (gloves, safety goggles, face shields, coveralls, and respirators) as indicated by the chemical hazard. OSHA’s general PPE standard (29 CFR 1910.132) and respiratory protection standard (29 CFR 1910.134) require this. 

• Train personnel for safe use, inspection, and maintenance of PPE. 

• Ensure that PPE is available in all areas where chemicals are kept or utilized. 

3) Ensure adequate ventilation 

• Ensure ventilation (e.g., exhaust fans, fume hoods) is in place to control airborne chemicals and reduce exposure to fumes. 

• Keep your air filtration systems working properly. 

• Do not enter a confined place without enough ventilation and proper respiratory protection. 

4) Safety training and education  

• To comply with OSHA, regular instruction on safe use, emergency procedures, and chemical hazards is necessary. 

• Training is reinforced with practical demonstrations and safety drills. 

• All workers must be able to read and understand the Safety Data Sheets (SDS) for the items they are dealing with.  

5) Preparing for chemical spills 

• Ensure spill kits with absorbents, neutralizers, and PPE are readily accessible and available. 

• Have a defined spill response plan: containment, evacuation, and notification. 

• Train people to use spill kits for small spills and major spills. 

6) Well documented and labeled  

• All containers of chemicals must be labeled with name, hazards, and safety precautions. This is regulated by OSHA’s Hazard Communication regulation (29 CFR 1910.1200) and the GHS labeling standards. 

• Maintain a current list of all compounds on site and their SDS. 

• Label consistently as per the Globally Harmonized System, or GHS 

7) Disposal of chemical waste safely 

• Dispose of chemical waste in accordance with local regulations. Note: Your team should be able to tell you whether your operation creates methylene chloride waste and spent solvents as hazardous waste under RCRA (40 CFR 261). 

• Use containers for hazardous garbage. Separate the many types of waste. 

• Dispose of rubbish responsibly and use professional garbage disposal companies to take care of it. 

8) Routine safety checks 

• Routine inspection of chemical storage, personal protective equipment, and emergency equipment is a must. 

• Check for leaks, rust, or damaged containers and make changes in time as required.  

• Document verification and corrective action for compliance.  

9) Chemical inventory management software 

• Design a digital system to record chemical quantities, their storage location, and expiration dates. 

• The program makes it easy to obtain SDS and safety rules. 

• Use technology for inspections, reporting, and compliance checks. 

Conclusion 

Chemicals are crucial in aircraft maintenance by ensuring safety, performance, and longevity. Proper handling, storage, and disposal of these chemicals are essential to protect workers, maintain compliance, and prevent environmental harm. By following safety best practices and staying informed, aviation maintenance facilities can create a secure workspace while keeping aircraft in optimal condition.   

Frequently asked questions 

1. Which aircraft maintenance chemicals require OSHA medical surveillance?  

Asbestos and methylene chloride both have their own OSHA standards that require medical surveillance for workers handling them in regulated conditions. This goes beyond the general PPE and ventilation guidance that applies to most other chemicals on this list. 

2. Is methylene chloride still legal to use in aviation paint stripping? 

As of this guide's last update, aviation and aerospace paint stripping on safety-critical, corrosion-sensitive aircraft parts has a time-limited exemption under the EPA's 2024 rule, but only for facilities that set up a Workplace Chemical Protection Program (WCPP) as required. Because this is an evolving area, confirm your facility's current status directly with EPA guidance or your compliance team before making decisions. 

3. What PPE is required for handling aircraft de-icing fluid (ethylene glycol)?  

Gloves and eye protection are the baseline. Since ethylene glycol is toxic if swallowed, secure storage that prevents mix-ups is just as important as PPE. 

4. Are CFCs still used in aviation maintenance?  

Yes, in some legacy ground equipment and systems. Handling, recovery, and disposal of CFC refrigerants requires EPA certification under the Clean Air Act, separate from standard worker-safety steps. 

5. What's the difference between a general PEL and a substance-specific OSHA standard?  

A general PEL (permissible exposure limit) sets a legal ceiling on how much of a chemical workers can be exposed to; that's it. A substance-specific standard, like the ones for asbestos and methylene chloride, adds extra legal requirements on top of the exposure limit: things like air monitoring, written exposure control plans, and required medical exams. If a chemical you use has a substance-specific standard, general PPE and ventilation guidance alone won't meet the legal requirement.