MDA substance technical guidelines

Under 1910.1050 App B, employees should wear appropriate personal protective equipment such as chemical-resistant gloves, protective clothing, and eye protection to prevent skin and eye contact with MDA.

• App B specifically states to “wear appropriate personal protective equipment.” See 1910.1050 App B.
• For head protection where there is a risk of falling objects or overhead hazards, employers must follow head protection rules in 29 CFR 1910.135 as explained in OSHA’s letter on head protection.

Under 1910.1050 App B, transfers of MDA should be done in well-ventilated areas and use good work practices to avoid spills because transfer operations can produce high exposure.

• App B states: “Such operations should be well ventilated and good work practices must be established to avoid spills.” See 1910.1050 App B.
• Use local exhaust ventilation (hoods) where dust, fumes, or heated vapors may form, and implement procedures and training to minimize exposure during filling, decanting, and sampling. Also ensure compliance with the main standard 1910.1050 for medical surveillance and other employee-protection requirements when applicable.

Under 1910.1050 App B, grinding or heating MDA increases the potential for employee exposure because these operations can generate airborne dusts or vapors.

• App B says: “Pure MDA is a solid with a low vapor pressure. Grinding or heating operations increase the potential for exposure.” See 1910.1050 App B.
• Controls: use local exhaust ventilation, enclosures, dust collection, appropriate respirators if engineering controls cannot maintain exposures below acceptable limits, and wear protective clothing to prevent skin contact. Follow the employer obligations in 1910.1050 when exposures may occur.

Under 1910.1050 App B, MDA should be stored away from strong oxidizing materials because it is incompatible with oxidizers.

• App B explicitly lists “Incompatibility: Strong oxidizers” and instructs to “Store away from oxidizing materials.” See 1910.1050 App B.
• Precautions: keep containers tightly closed, store in a cool dry place per the material’s temperature limits (MDA melts at 88–93 °C), label containers, and implement inventory control to limit quantities on site consistent with workplace practices and applicable regulations in 1910.1050.

Under 1910.1050 App B, for small spills of solid MDA, sweep the material onto paper, place it in a fiber carton or appropriate container, and prepare it for safe disposal.

• App B gives specific spill steps: “Sweep material onto paper and place in fiber carton.” See 1910.1050 App B.
• Follow-up: control dust during cleanup, use appropriate PPE, avoid generating airborne dust, and arrange disposal per the guidance in App B (incineration or licensed chemical waste service) and applicable environmental and waste regulations referenced in 1910.1050.

Under 1910.1050 App B, MDA waste should be packaged and either fed to an approved incinerator with an afterburner and scrubber or handled by a licensed chemical waste disposal service.

• App B recommends: “Package appropriately for safe feed to an incinerator or dissolve in compatible waste solvents prior to incineration” and “Dispose of in an approved incinerator equipped with afterburner and scrubber or contract with licensed chemical waste disposal service.” See 1910.1050 App B.
• Note: Disposal may also be subject to federal, state, or local environmental laws; coordinate with your environmental compliance officer or a licensed waste hauler and follow employer obligations in 1910.1050.

Under 1910.1050 App B, firefighters should use water spray, dry chemical, or carbon dioxide to extinguish fires and must wear self-contained breathing apparatus (SCBA) and protective clothing to prevent skin and eye contact.

• App B lists extinguishing media and special procedures: “Extinguishing Media: Water spray; Dry Chemical; Carbon dioxide” and “Wear self-contained breathing apparatus and protective clothing to prevent contact with skin and eyes.” See 1910.1050 App B.
• App B also warns that combustion may produce hazardous decomposition products such as carbon monoxide and oxides of nitrogen; ensure fire crews use SCBA and follow the employer’s emergency response plan under 1910.1050.

Under 1910.1050 App B, MDA is stable under normal conditions but is incompatible with strong oxidizers and may produce toxic combustion products when burned.

• App B states: “Stability: Stable,” “Incompatibility: Strong oxidizers,” and warns that combustion may produce carbon monoxide and oxides of nitrogen. See 1910.1050 App B.
• Controls: segregate MDA from oxidizers, maintain proper storage conditions, and include reactivity hazards in your emergency response and hazard communication program required by 1910.1050 and other applicable OSHA standards.

Under 1910.1050 App B, MDA is slightly soluble in cold water but very soluble in alcohol, benzene, ether, and many organic solvents, so solvent-based cleanups can dissolve MDA and must be handled carefully.

• App B lists solubility: “Slightly soluble in cold water, very soluble in alcohol, benzene, ether, and many organic solvents.” See 1910.1050 App B.
• Guidance: use compatible solvents only if recommended by your safety data sheet (SDS), control vapors with ventilation, wear appropriate PPE, and dispose of solvent wastes per the disposal guidance in App B and applicable environmental rules referenced in 1910.1050.

Under 1910.1050 App B, employers should keep the workplace clean, institute a leak and spill detection program for MDA operations, and provide adequate hot and cold washing facilities plus suitable cleansing agents for effective skin decontamination.

• App B states: “The workplace should be kept clean, orderly, and in a sanitary condition,” recommends a leak and spill detection program, and says “Adequate washing facilities with hot and cold water are to be provided… Suitable cleansing agents should also be provided.” See 1910.1050 App B.
• Employers must also meet the employer and employee-protection provisions in 1910.1050 and general PPE/housekeeping rules in 1910.

Under 1910.1050 App B, employers shall advise employees of all areas and operations where exposure to MDA could occur.

• App B uses the mandatory phrasing: “Employers shall advise employees of all areas and operations where exposure to MDA could occur.” See 1910.1050 App B.
• This advice should be part of your hazard communication, training, and access control programs required under 1910.1050 and general OSHA rules in 1910.

Under 1910.1050 App B, common operations with likely MDA exposure include manufacturing MDA, manufacturing methylene diisocyanate, using MDA as a curing agent for epoxy resins, wire coating operations, and filament winding.

• App B lists these common operations explicitly: “Manufacture of MDA; Manufacture of Methylene diisocyanate; Curing agent for epoxy resin structures; Wire coating operations; and filament winding.” See 1910.1050 App B.
• Employers in these processes should assess exposures and implement controls such as ventilation, PPE, and training under 1910.1050.

Under 1910.1050 App B, employers should institute a leak and spill detection program to detect sources of fugitive MDA emissions and maintain good housekeeping to control contamination.

• App B advises: “The employer should institute a leak and spill detection program for operations involving MDA in order to detect sources of fugitive MDA emissions.” See 1910.1050 App B.
• Follow-up actions should include prompt repair, containment, cleaning, monitoring, employee notification, and training as part of the hazard communication and exposure control obligations in 1910.1050.

Under 1910.1050 App B, vapor exposure to MDA at normal room temperatures is generally low because MDA is a solid with negligible evaporation and low vapor pressure, but airborne exposure can occur if the material is heated, ground, or aerosolized.

• App B notes: “Pure MDA is a solid with a low vapor pressure” and lists “Evaporation Rate: Negligible” and “Vapor Pressure: 9 mmHg at 232 degrees C,” while warning that grinding or heating increases exposure potential. See 1910.1050 App B.
• Controls should focus on preventing dust generation, local exhaust when heating/grinding, and respiratory protection when engineering controls cannot limit airborne levels per 1910.1050.

Under 1910.1050 App B, head protection is required when workers are in areas with potential for head injury from falling objects or overhead hazards while handling MDA.

• While App B stresses PPE for handling MDA, OSHA’s head protection rule requires helmets where there is a risk of head injury; see the OSHA head protection interpretation: 29 CFR 1910.135.
• Employers must evaluate the work area and provide protective helmets compliant with applicable ANSI consensus standards when overhead hazards exist, and include this in the hazard assessment required by 1910.1050.

Under 1910.1050 App B, employers should provide necessary protective clothing, prevent contaminated clothing from being worn outside the work area, and provide washing facilities and cleansing agents so employees can remove any MDA from skin.

• App B instructs to “Wear appropriate personal protective equipment” and to provide “Adequate washing facilities with hot and cold water… Suitable cleansing agents” for removing MDA from skin. See 1910.1050 App B.
• Practical steps: provide disposable or launderable protective clothing, establish doffing/decon procedures, provide on-site laundering or separate storage for contaminated clothing, and include these controls in your overall exposure control plan per 1910.1050.

Under 1910.1050 App B, the guidance recommends that employers institute a leak and spill detection program for MDA operations, but App B is advisory guidance; employers must still meet the substantive workplace-protection requirements in [1910.1050].

• App B states: “The employer should institute a leak and spill detection program for operations involving MDA in order to detect sources of fugitive MDA emissions.” See 1910.1050 App B.
• Employers should treat this recommendation as part of an effective exposure control plan and ensure compliance with the requirements and recordkeeping, training, and medical provisions in 1910.1050.