MSA 815178 GMA-P100 Organic Vapor / P100 Cartridge for Comfo Respirators — Box of 6

MSA GMA-P100 Overview

The MSA GMA-P100 is a NIOSH-approved combination cartridge that pairs an activated carbon organic vapor bed with a P100 (99.97% efficient) particulate filter in a single bayonet-mount unit — sold as a box of 6 cartridges at $120.57 ($20.10 per cartridge). It attaches via the threaded bayonet connection used across the MSA Comfo and GM respirator series, making it a direct-fit replacement for workers already using MSA full-face respirators or MSA half-mask respirators in that line. Before committing to this cartridge, confirm your hazard profile using the respirator cartridge selection guide and review the organic vapor vs. P100 comparison to understand when a combination cartridge is the right call versus a particulate-only filter.

Affiliate disclosure: WC Safety earns a commission on Amazon purchases at no cost to you.

Where the GMA-P100 Fits in Respirator Selection

Start with hazard confirmation, not cartridge shopping. If your Safety Data Sheet (SDS) lists organic vapors and particulate dust, mist, or fume at or above action levels, a combination OV/P100 cartridge is the correct class. The GMA-P100 covers that pairing. If your hazards also include acid gases, chlorine, or ammonia, you need a broader cartridge — see the MSA GMC-P100 or MSA GME-P100 multigas/particulate cartridge for those applications. The respirator filter types guide explains how NIOSH cartridge designations map to hazard classes, and the respirator cartridge color chart helps you verify you're grabbing the right cartridge at the job-site level.

Who Should Buy the GMA-P100?

Buy the GMA-P100 if:

• You work with solvent-based paints, coatings, or adhesives that also generate fine particulate (dust, overspray mist, weld fume).
• Your respirator is already in the MSA Comfo Classic, Comfo II, Ultra-Twin, or Ultra-Elite family and you need a replacement cartridge.
• Your industrial hygienist has specified an OV/P100 combination under an established respiratory protection program.
• You want the cost efficiency of a 6-pack at $20.10 per cartridge versus single-cartridge pricing.

Don't buy the GMA-P100 if:

• Your only hazard is particulate — the MSA Low Profile P100 filter is a lower-cost particulate-only option.
• You need acid gas protection — the MSA GMB-P100 Acid Gas/P100 cartridge or MSA GMC-P100 is the correct choice.
• You own an MSA Advantage-series respirator — Advantage respirators use a snap-on connection, not the Comfo bayonet mount.
• You own a 3M, Honeywell, or Moldex respirator — MSA cartridges are brand-specific and not cross-compatible.

What Does the GMA-P100 Protect Against?

What the GMA-P100 Does NOT Protect Against

• Acid gases (chlorine, hydrogen chloride, sulfur dioxide, hydrogen fluoride) — use the MSA GMB-P100 or MSA GMC-P100 for those hazards.
• Ammonia and methylamine — the MSA GMD-P100 is the correct cartridge for ammonia environments.
• Mercury vapor — requires the MSA Mersorb P100 mercury vapor cartridge.
• Iodine / radioactive particulate — see the MSA GMI Iodine/P100 cartridge.
• Carbon monoxide, hydrogen, or other gases not listed on NIOSH approval — no air-purifying cartridge is approved for CO.

Best Applications for the MSA GMA-P100

Spray Painting and Automotive Refinishing

Solvent-borne paints, lacquers, and clear coats generate both organic vapor (from solvents like acetone, MEK, and toluene) and fine paint mist. The GMA-P100's dual filtration covers both hazards simultaneously, making it the standard cartridge choice in auto body and industrial spray booth environments. See the MSA full-face respirator collection if your spray work requires eye and face protection in addition to respiratory protection.

Chemical and Petrochemical Plant Maintenance

Maintenance tasks involving solvent cleaning, degreasing, or equipment servicing in process environments often generate simultaneous vapor and particulate exposure. The P100 layer handles catalytic dust and metal fume while the carbon bed addresses the volatile organic component. Workers in these environments should review the how-to-choose-a-respirator-cartridge guide to confirm the GMA-P100 covers all hazardous components on their SDS before use.

Industrial Coatings and Adhesive Application

Epoxy coatings, urethane adhesives, and contact cements release organic vapor throughout application and cure. When those operations also generate sanding dust or adhesive overspray, the combination OV/P100 cartridge eliminates the need for stacked filter assemblies. Pair with the appropriate MSA half-mask respirator for tasks where full-face coverage is not required.

Welding in Solvent-Contaminated Environments

Welding on solvent-cleaned or coated metals introduces both weld fume (particulate) and volatilized coating components (organic vapor). The GMA-P100 handles that mixed-hazard scenario. Workers in dedicated welding environments without solvent vapors may prefer a particulate-only option — compare options in the best respirator for welding fumes guide.

Pros and Cons

Compatible MSA Respirators

The GMA-P100 uses the MSA Comfo/GM threaded bayonet mount. Verify your specific respirator model's connection type before ordering.

GMA-P100 vs Other MSA Filters and Cartridges

All cartridges below use the MSA Comfo/GM bayonet mount. Browse the full MSA respirator filters and cartridges collection for pricing and availability.

GMA-P100 vs GMC-P100 — Organic Vapor + Acid Gas + P100

The MSA GMC-P100 is the direct step-up from the GMA-P100 for environments where acid gases (chlorine, hydrogen chloride, sulfur dioxide) are present alongside organic vapors and particulate. Both use the same bayonet mount and P100 particulate layer. The GMC-P100 adds an acid gas sorbent bed that the GMA-P100 lacks. If your SDS lists any acid gas components, the GMC-P100 is the correct choice; the GMA-P100 provides no protection against those hazards.

GMA-P100 vs GMA — Organic Vapor Only

The MSA GMA organic vapor cartridge covers the same OV hazard class without a particulate filter. Choose the GMA when your environment has only vapor exposure and no dust, mist, or fume; choose the GMA-P100 when fine particulate is also present. The GMA is typically priced lower, so using it in a particulate-free environment avoids spending on P100 filtration capacity you don't need.

GMA-P100 Quick Answers

What does P100 mean on the GMA-P100?

P100 is a NIOSH particulate efficiency class indicating the filter removes at least 99.97% of airborne particles 0.3 microns and larger, including oil-based aerosols. It is the highest particulate rating available for air-purifying respirators under NIOSH 42 CFR Part 84. The "P" designation means it is oil-proof, making it suitable for environments with oil mist or aerosols in addition to dry particulate.

How long does the GMA-P100 cartridge last?

Organic vapor cartridge service life depends on vapor concentration, relative humidity, temperature, breathing rate, and the specific chemicals present. There is no fixed hour-based replacement schedule — follow your employer's change-out schedule established under OSHA 29 CFR 1910.134, or replace the cartridge at the first detection of odor or taste of the contaminant. The P100 filter layer does not have a vapor-breakthrough issue but should be replaced when airflow resistance increases noticeably or the cartridge is damaged.

Will the GMA-P100 fit my MSA Advantage respirator?

No. MSA Advantage-series respirators use a snap-on cartridge connection that is not compatible with GMA-series bayonet-mount cartridges. The GMA-P100 fits only MSA Comfo Classic, Comfo II, Ultra-Twin, and Ultra-Elite respirators that use the Comfo/GM threaded bayonet mount. Check your respirator's user manual or look for the MSA GM part-number designation to confirm compatibility before ordering.

Can I use the GMA-P100 for silica dust?

Yes. The P100 filter layer exceeds the NIOSH recommendation for crystalline silica protection and provides higher filtration efficiency than the minimum N95 class sometimes cited for silica. The GMA-P100 is appropriate when silica dust exposure co-occurs with organic vapor — for silica-only environments without vapor, a P100-only filter is more cost-effective. See the best respirator for silica dust guide for a full comparison of filter options.

How many cartridges are in a box?

The GMA-P100 is sold in a box of 6 cartridges at $120.57 total, which works out to $20.10 per cartridge. The pack is designed for industrial procurement and compliance stocking — there is no single-cartridge listing at this price point.

Is the GMA-P100 NIOSH-approved?

Yes. The GMA-P100 is NIOSH-approved under 42 CFR Part 84 for combination organic vapor and P100 particulate service. MSA Safety publishes the NIOSH approval number on the cartridge label and in the product documentation. Always verify the NIOSH approval number on the physical cartridge before placing workers in service.

Does the GMA-P100 protect against welding fumes?

The P100 filter layer in the GMA-P100 captures welding fume particulate (metal oxide aerosols) at 99.97% efficiency. The organic vapor component also captures volatilized coating compounds from coated-metal welding. For welding on uncoated metals without solvent vapor, a P100-only filter may suffice at lower cost. Review the best respirator for welding fumes guide for a full breakdown by welding process.

MSA GMA-P100 Specifications

Helpful Buying Guides

• How to Choose a Respirator Cartridge — Complete Selection Guide
• Respirator Filter Types Explained — N95, P100, OV, and Combination Classes
• Organic Vapor vs. P100: When to Use Each and When to Combine
• Respirator Cartridge Color Chart — NIOSH Color Codes Decoded
• Best Respirator for Silica Dust 2026 — P100 and Half-Mask Comparison
• Best Respirator for Welding Fumes — Filter and Cartridge Comparison

MSA GMA-P100 Frequently Asked Questions

Is the GMA-P100 the right cartridge for spray painting with solvent-based coatings?

Yes, for most spray painting applications with solvent-borne coatings the GMA-P100 is the appropriate cartridge class. Solvent-based paints release organic vapors (acetone, toluene, MEK, and similar) and generate fine paint mist particulate during application — exactly the dual-hazard combination the OV/P100 rating covers. Confirm by reviewing the SDS for each coating product to verify no acid gas components are listed; if acid gases are present, step up to the MSA GMC-P100.

Can I use the GMA-P100 cartridge with an MSA full-face respirator?

Yes. The GMA-P100 fits MSA full-face respirators in the Comfo series — including the Ultra-Twin and Ultra-Elite — that use the Comfo/GM bayonet mount. Full-face use raises the APF from 10 (half-mask) to 50, which is necessary when contaminant concentrations exceed 10 times the permissible exposure limit (PEL) or when eye and face protection are also required.

How do I know when to replace the GMA-P100 cartridge?

Replace the GMA-P100 immediately if you detect odor, taste, or irritation while wearing the respirator — these are signs of organic vapor breakthrough through the carbon bed. For scheduled replacement, follow the change-out schedule in your employer's written respiratory protection program, which must be established under OSHA 29 CFR 1910.134. The P100 filter layer should also be replaced when breathing resistance increases noticeably or when the cartridge is visibly soiled or damaged.

Does the GMA-P100 protect against isocyanates?

Isocyanates (such as MDI and TDI in two-component polyurethane coatings) present as both vapor and aerosol. The P100 filter captures isocyanate aerosol particles, and the organic vapor carbon bed provides some adsorption of isocyanate vapors. However, isocyanate protection requirements often mandate supplied-air respirators at higher concentrations due to their extreme sensitization hazard. Always consult your industrial hygienist and the coating manufacturer's SDS for the specific respiratory protection recommendation before relying on an air-purifying cartridge for isocyanate work.

How many GMA-P100 cartridges does one box contain?

Each box contains 6 cartridges. At $120.57 per box, the per-cartridge cost is $20.10. For a half-mask respirator that uses one cartridge per side, one box provides 3 complete cartridge-change-outs per respirator.

Can the GMA-P100 be used for pesticide application?

Many agricultural and commercial pesticide formulations require an OV/P100 combination respirator, and the GMA-P100 meets that class. Always verify the pesticide product label — in the United States, pesticide respirator requirements are federally mandated on the product label and may specify a minimum assigned protection factor or a specific cartridge class. Confirm that organic vapor is the relevant hazard (rather than acid gas or ammonia) before selecting the GMA-P100 for pesticide applications.

What is the difference between the GMA-P100 and the GMC-P100?

The GMA-P100 covers organic vapor plus P100 particulate. The GMC-P100 covers organic vapor, acid gas, and P100 particulate — it adds an acid gas sorbent bed. If your environment contains chlorine, hydrogen chloride, sulfur dioxide, or similar acid gases in addition to organic vapors and particulate, the GMC-P100 is required. The GMA-P100 provides no acid gas protection.

Is the GMA-P100 approved for use in paint spray booths?

The GMA-P100's OV/P100 combination is the standard cartridge class for automotive and industrial spray booth environments where solvent-borne coatings are applied. OSHA and NIOSH guidance for spray finishing operations commonly specifies OV/P100 combination respirators. The specific booth and coating application must still be evaluated by a competent person to confirm the GMA-P100's OV service life is adequate for the spray duration and solvent concentration.

Does the GMA-P100 filter oil mist?

Yes. The "P" designation in P100 stands for oil-proof, meaning the filter is rated for environments containing oil aerosols or mist. It maintains its 99.97% efficiency rating in the presence of oil-based particles, unlike N-class filters (which are not oil-tested) or R-class filters (which are oil-resistant for only 8 hours). The GMA-P100 is appropriate for machining, metalworking, or any environment where oil mist is present alongside organic vapor.

Can I store unused GMA-P100 cartridges and use them later?

Unopened GMA-P100 cartridges should be stored in their original sealed packaging in a cool, dry location away from direct sunlight, heat sources, and chemical vapors. Once opened, the activated carbon bed begins to adsorb ambient vapors even when not in use, degrading the organic vapor service life. Follow MSA's published shelf-life guidance and your employer's respiratory protection program — do not use cartridges whose packaging is damaged or whose seal has been broken without tracking the storage duration.

What respiratory protection do I need if the GMA-P100 is not adequate for my hazard?

If contaminant concentrations exceed the cartridge's service life capacity, are IDLH, or if the hazard includes gases not covered by the OV designation, a supplied-air respirator (SAR) or self-contained breathing apparatus (SCBA) is required. Those situations fall outside air-purifying respirator use entirely. For multi-gas environments within air-purifying APF limits, evaluate the MSA GME-P100 multigas/particulate cartridge for broader chemical coverage under a single cartridge class.

Are there 3M or Moldex alternatives to the GMA-P100?

3M and Moldex both offer OV/P100 combination cartridges for their respective respirator platforms, but those cartridges are not compatible with MSA respirators. If you own an MSA Comfo-series respirator, you must use MSA cartridges. If you are evaluating respirator platforms across brands, compare options in the 3M respirator filters and cartridges collection and the Moldex respirator cartridges and filters collection — but note that switching cartridge brands requires a compatible respirator facepiece.