MSA GMD P100 Cartridge Review: Ammonia Plus Particulate

Is the MSA 815181 GMD-P100 the right cartridge for ammonia exposure with dust?

Published June 10, 2026 · Last updated July 27, 2026

Short answer: Yes — when your hazard assessment documents both ammonia (or methylamine) and respirable particulates, the MSA 815181 GMD-P100 is the correct single-cartridge answer on the Comfo platform. It is the only MSA GM-series cartridge that pairs the dedicated NH₃/methylamine sorbent with an integrated P100 filter rated at 99.97% particulate efficiency. If your documented hazard is ammonia alone with no dust co-exposure, the simpler MSA 464033 GMD at roughly half the per-unit cost is the better value. If your hazard extends to additional inorganic gases (chlorine, hydrogen sulfide, sulfur dioxide), step up to the MSA 815182 GME-P100.

The MSA 815181 GMD-P100 occupies a specific and important niche in the MSA GM-series cartridge lineup: alkaline gas protection paired with particulate filtration in a single bayonet unit. Sold in boxes of six at its listed price (its listed price per cartridge), it targets the refrigeration technician working near fibrous insulation, the wastewater operator exposed to both ammonia off-gassing and respirable dust, and the agricultural or fertilizer-handling worker dealing with simultaneous NH₃ and silica dust co-exposure. This review covers what the 815181 does well, where it runs short, how it compares within the MSA GM-series, and which Comfo-platform respirators it's compatible with.

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Editorial verdict — MSA 815181 GMD-P100: 4.5/5
The MSA 815181 GMD-P100 is the correct cartridge when NH₃/methylamine and particulate co-exposure are both documented — it eliminates the need for a separate prefilter stack and is the only GM-series option providing P100-level dust protection alongside alkaline gas sorbent. At its listed price per cartridge it carries a real premium over the gas-only GMD, so verify that both hazards exist before specifying it.

View the listing Check the price on Amazon

Who the MSA 815181 GMD-P100 is for

• Refrigeration system maintenance technicians working near ammonia refrigerant lines in environments with fibrous insulation or pipe-lagging dust
• Wastewater treatment operators exposed to ammonia/hydrogen sulfide off-gassing plus fine particulate from biosolids handling — though note H₂S requires a GME or GME-P100 step-up
• Fertilizer and agricultural chemical handlers where anhydrous or aqueous ammonia co-exists with respirable grain dust or silica
• Biogas facility workers in anaerobic digestion operations where NH₃ and particulate are both present
• Pulp-and-paper workers using ammonia-based process chemicals in dusty environments where only alkaline gas hazard is documented
• Industrial hygienists specifying Comfo-platform programs who need the P100 particulate tier without stepping up to a full multi-gas cartridge

If your exposure is ammonia with no significant dust co-exposure, check the MSA 464033 GMD for lower cost. Browse the complete MSA respirator filters and cartridges collection for the full Comfo series lineup.

What the MSA 815181 GMD-P100 does well

P100 particulate protection integrated at the cartridge level

The GMD-P100's defining advantage over the base MSA 464033 GMD is the integrated NIOSH P100 filter media, rated ≥99.97% efficient against 0.3 μm test aerosol under 42 CFR Part 84. In ammonia environments that also generate respirable particulate — insulation fiber, biosolids aerosol, silica from fertilizer handling — the 815181 eliminates the need to stack a separate P100 prefilter disc and retainer on top of a gas-only cartridge. Fewer components means a lower-profile assembly and one less maintenance item to track.

Dedicated alkaline gas sorbent validated by NIOSH

The "D" designation in MSA's GM-series coding identifies the alkaline gas sorbent formulation — the same chemistry used in the gas-only MSA 464033 GMD. NIOSH approval under 42 CFR Part 84 certifies the sorbent against both ammonia (NH₃) and methylamine (CH₃NH₂) — two of the most common alkaline/amine gas hazards in industrial settings. That dual coverage is relevant in wastewater treatment and chemical manufacturing where both compounds may appear. The P100 layer in the 815181 does not degrade the gas-phase sorbent performance.

Comfo platform breadth — half-mask and full-face compatibility

The MSA GM threaded mount connects the 815181 to both Comfo half-masks (MSA Advantage 200 LS, Comfo Classic, Comfo II) and to the full-face MSA Ultra-Elite and Ultra-Twin. A single cartridge type spans both APF 10 (half-mask) and APF 50 (full-face) facepieces — a meaningful administrative simplification for industrial hygiene programs managing multiple protection factor tiers. When upgrading from half-mask to full-face doesn't require a new cartridge specification, hazard-control transitions are simpler to document.

Predictable dual-hazard compliance documentation

OSHA 29 CFR 1910.134 requires that cartridge selection be justified in writing against the documented inhalation hazards. When both ammonia and particulate appear in the hazard assessment, specifying a single NIOSH-approved combination cartridge — the 815181 — produces cleaner written programs than specifying a gas cartridge and particulate filter separately and managing two distinct approved-equipment records. Confirm the approval number for your part on the NIOSH Certified Equipment List.

Where the MSA 815181 GMD-P100 falls short

No organic vapor or acid gas coverage

The GMD-P100's sorbent addresses only alkaline gases. It provides zero protection against organic vapors (solvents, hydrocarbons, VOCs), chlorine, hydrogen chloride, sulfur dioxide, or hydrogen sulfide. In wastewater treatment where H₂S co-exists with NH₃, the GMD-P100 is the wrong selection — the MSA 815182 GME-P100 covers nine inorganic gases including both. Facilities with co-exposure to organic vapors and ammonia need the MSA GMC-P100 (OV + acid gas) or a hazard-specific GMC variant reviewed against the full chemical list.

Price premium requires a verified dual-hazard case

At its listed price per cartridge, the 815181 costs approximately twice the base MSA 464033 GMD (its listed price/unit). That premium is fully justified when particulate co-exposure is documented — but unjustifiable as a precautionary over-spec when dust is not a documented hazard. Industrial hygienists performing air monitoring should confirm whether respirable particulate concentrations exceed action levels before specifying the P100 tier; otherwise the simpler GMD preserves budget without reducing protection against the actual hazard.

No end-of-service-life indicator

Like all GM-series cartridges, the 815181 lacks an ESLI. Ammonia has a strong odor that can serve as a rough breakthrough warning at higher concentrations, but OSHA 29 CFR 1910.134(d)(3)(iii) does not allow reliance on odor for change-out scheduling at all. The rule requires an end-of-service-life indicator or a change schedule built from objective data, and there is no exemption for contaminants with good warning properties. A written change schedule built from objective data, using a recognized service-life model is mandatory for compliant programs — this adds an administrative burden not present with ESLI-equipped cartridges.

Incompatibility outside the Comfo/Ultra-Twin platform

The GM threaded mount is proprietary to MSA's Comfo platform. It does not mate with MSA's own Advantage snap-on series, 3M bayonet-mount cartridges, Moldex cartridges, or any other manufacturer's facepiece. Organizations running a mixed-manufacturer respirator fleet cannot rationalize to a single cartridge — a meaningful procurement complexity for large programs.

MSA 815181 GMD-P100 vs comparable ammonia/P100 cartridges

Table note: The MSA Advantage GMD uses a different snap-on mount and is not interchangeable with the Comfo-platform cartridges above. Verify facepiece compatibility before ordering.

MSA GMD on Amazon → MSA GME-P100 on Amazon →

MSA GMD series: gas-only vs GMD-P100

• Buy the MSA 464033 GMD if: Your written hazard assessment documents only NH₃ and/or methylamine with no significant respirable particulate co-exposure. Use the savings to fund a more frequent change-out schedule.
• Buy the MSA 815181 GMD-P100 if: Particulate is documented alongside ammonia — refrigeration work with pipe insulation disturbance, fertilizer handling with grain dust, biogas operations with biosolids aerosol. The integrated P100 eliminates filter-stacking complexity.
• Step up to the MSA 815182 GME-P100 if: Your hazard assessment includes any acid gases (Cl₂, HCl, SO₂), H₂S, formaldehyde, or hydrogen fluoride in addition to ammonia and dust.

View the GMD series on Amazon → listing MSA GMD (gas only) MSA 815181 GMD-P100

A combination cartridge carries two approvals — and two change triggers

This is the point most often missed on combination media. A gas-plus-P100 cartridge is approved twice over: once for the gas or vapor its sorbent is rated against, and once as a P100 particulate filter at 99.97 percent. Neither half covers the other. The sorbent does nothing for dust, fume or mist, and the P100 layer does nothing for gases or vapors — it simply sits in the same housing.

Because the two halves fail differently, they need different replacement rules and the earlier of the two governs. The sorbent is replaced on an end-of-service-life indicator where one exists, or otherwise on a change schedule built from objective data, as OSHA 1910.134(d)(3)(iii) requires — never on smell or taste. The particulate filter loads rather than breaks through, so its practical trigger is increased breathing resistance, along with damage, soiling or contamination. A cartridge whose filter side is still breathing freely can be well past its sorbent life, and a cartridge that has become hard to breathe through must come off regardless of how much sorbent capacity remains. The combination does not extend the life of either half.

One consequence for cost: combination cartridges are replaced on the shorter of the two clocks, so per-cartridge price is a poor guide to running cost. Confirm the approval covering your exact part on the NIOSH Certified Equipment List — the approved-substance list and any escape-only qualifiers are properties of the approval, not of the marketing description.

What a “multi-gas” cartridge does and does not cover

MSA’s letter codes name a specific approved list, not a general capability. The GMA is organic vapor; GMB acid gas; GMC organic vapor plus acid gas; GMD ammonia and methylamine; and the multi-gas GME and GMT cover a broader but still enumerated set. “Multi-gas” never means “any gas”. Each approval names the substances, and several carry qualifiers that matter more than the headline — MSA lists hydrogen sulfide on the GME for escape only, which is a different duty entirely from working in it.

Two limits apply no matter which letter is on the cartridge. No air-purifying cartridge removes carbon monoxide. CO is not adsorbed by the sorbents used in these cartridges, so a CO hazard is answered by ventilation, monitoring, and supplied air — never by a cartridge, whatever its multi-gas designation. And a gas or vapor cartridge does nothing for particulate: dust, fume, mist and lead need a particulate filter, which is why the combination parts exist. Read the approved-substance list for the exact part number against your air monitoring, and where the contaminant or its concentration is unknown, the answer is not a broader cartridge — it is measurement, or supplied air.

These cartridges only fit MSA facepieces

Cartridge connections are proprietary. MSA Advantage and Comfo cartridges thread onto MSA facepieces and nothing else — they do not fit 3M bayonet respirators, Honeywell North, or Moldex, and no adapter makes that combination approved. This matters beyond convenience, because a NIOSH approval covers a complete assembly: a specific facepiece with specific media. Mixing a cartridge from one manufacturer onto another’s facepiece voids the approval even if the parts physically engage, which means the respirator is no longer NIOSH-approved equipment for the purposes of OSHA 1910.134.

The practical rule when restocking: match the cartridge to the facepiece brand first, then to the hazard. Confirm the approval covering your exact combination on the NIOSH Certified Equipment List rather than from a listing, and check the letter designation printed on the cartridge against what your hazard assessment calls for. Where a program runs more than one brand of facepiece, the stores that go with each need to be physically separated — the most common way the wrong cartridge reaches a face is a shared bin.

When to change a cartridge — and why “when I smell it” is not the answer

OSHA 1910.134(d)(3)(iii) is explicit: where gas or vapor cartridges are used, the employer must either fit them with an End of Service Life Indicator approved for the contaminant, or implement a change schedule based on objective information or data that ensures cartridges are replaced before the end of their service life. Relying on odor, taste, or irritation as the primary signal is not one of the permitted options, and the reason is straightforward: many contaminants have poor warning properties, individual sensitivity varies widely, and by the time a vapor is detectable inside the facepiece the breakthrough has already happened.

Mercury is the sharpest illustration. Mercury vapor has no odor at all, which is exactly why NIOSH-approved mercury cartridges carry a colorimetric ESLI — the indicator changes color as the sorbent loads, giving the wearer a visible end-of-service signal that a nose cannot provide. Particulate filters follow a different rule: they load rather than break through, so the practical trigger is increased breathing resistance, along with damage, soiling, or contamination of the filter. Replace a particulate filter when it becomes harder to breathe through, and never wash or attempt to clean filter media.

What has to be in place before anyone wears this

A respirator is the one piece of PPE that comes with a program attached. Where respirators are required, OSHA 1910.134 obliges the employer to run a written respiratory protection program with a named administrator, and four elements govern whether the equipment on this page will actually protect the person wearing it.

Medical evaluation comes first. Under 1910.134(e), a worker must be medically evaluated — using the Appendix C questionnaire or an equivalent examination — before fit testing or use, because breathing through a respirator imposes real physiological load. Fit testing is annual and model-specific under 1910.134(f): a passing test on one make, model and size does not transfer to another, so changing facepiece or size means testing again. Facial hair that crosses the sealing surface prohibits use — this is not a grooming preference but a seal failure, and no amount of strap tension compensates. And a user seal check goes on every single donning, per Appendix B-1, which takes seconds and is the only check that happens at the moment of use. Cartridge and filter selection follows from air monitoring and a hazard assessment; where the contaminant or its concentration is unknown, the answer is not a better cartridge.

The rest of the MSA Comfo cartridge range

Each combination cartridge has a gas-only sibling, and the choice between them is simply whether particulate is present. For acid gas there is the GMB and its GMB-P100; for organic vapor plus acid gas the GMC and GMC-P100; for ammonia and methylamine the GMD and GMD-P100; and for the multigas list the GME and GME-P100. Two specialist combinations have no gas-only twin: the GMI for radioiodine and the MerSorb-P100 for mercury vapor. Where particulate is the only hazard, the 815177 low-profile P100 covers it alone. Facepieces sit under MSA half mask respirators and MSA full face respirators, media under MSA respirator filters and cartridges.

Why trust WC Safety

WC Safety is an independent, affiliate-supported review site. We hold no inventory, sell nothing directly, and earn only from qualifying purchases made through clearly marked links — which never changes what a cartridge is approved to do. Reviews are compiled by Steven Eaton from MSA’s published technical data, the NIOSH approval record, the live listing, and the standards themselves (42 CFR 84, OSHA 1910.134) linked throughout. We hold no laboratory and run no breakthrough or fit testing, and we publish no customer-rating aggregate for any product, because we have no customers to aggregate. Where the published record is silent we say so rather than fill the gap.

Our methodology

This review is compiled from MSA’s published cartridge literature, the NIOSH approval record, the live listing, and the regulatory text. The score is an editorial judgment of approval fit, facepiece compatibility, hazard coverage and value — not a measured result, not a breakthrough test, and not an average of user ratings. Approved substances and the approval number for your exact part should be confirmed on the NIOSH Certified Equipment List and on the cartridge itself; where a listing and an approval disagree, the approval governs.

Researched and written by Steven Eaton, editor of WC Safety. Steven holds no safety certification and does not test products; this page compares what manufacturers publish, with the gaps in that record marked. Last reviewed July 2026.

More questions on this topic

Is the MSA 815181 GMD-P100 NIOSH-approved?

Yes. The MSA 815181 GMD-P100 is NIOSH-approved under 42 CFR Part 84 for both the alkaline gas (ammonia and methylamine) sorbent and the integrated P100 particulate filter. NIOSH 42 CFR Part 84 is the federal standard governing approval of air-purifying respirator cartridges and filters. Verify the current approval certificate against the NIOSH Certified Equipment List at NIOSH NPPTL CEL.

MSA GMD-P100 vs MSA GMD — which should I buy?

Buy the MSA 815181 GMD-P100 if your hazard assessment documents both ammonia (or methylamine) AND respirable particulates in the same work environment. Buy the MSA 464033 GMD (gas-only, approximately its listed price/unit) if particulate is not a documented inhalation hazard. Paying for an integrated P100 filter layer you don't need wastes budget without improving protection against the actual hazard. Confirm via air monitoring before specifying the P100 tier. See the MSA GMD gas-only review for the full comparison.

Does the MSA 815181 GMD-P100 protect against hydrogen sulfide?

No. The GMD-P100 sorbent is specific to alkaline gases — ammonia and methylamine. Hydrogen sulfide (H₂S) is an acid gas that is not captured by the GMD sorbent. In wastewater treatment environments where both NH₃ and H₂S are present, the MSA 815182 GME-P100 is the correct selection — it covers nine inorganic gases including both ammonia and hydrogen sulfide, plus P100 particulate. Read the MSA 815182 GME-P100 review for the full comparison.

Does the MSA GMD-P100 protect against organic vapors or solvents?

No. The GMD-P100 contains no organic vapor sorbent. Solvents, petroleum distillates, ketones, esters, and other VOCs will pass through the cartridge without being captured. If your hazard assessment includes both organic vapors and ammonia, you need a combined OV+AG or custom cartridge selection — the MSA GM-series does not offer a GMD+GMA combination in a single cartridge. Consult your industrial hygienist for the correct specification.

What respirators are compatible with the MSA 815181 GMD-P100?

The MSA 815181 GMD-P100 uses the MSA GM threaded mount, compatible with: Comfo Classic half-mask, Comfo II half-mask, MSA Ultra-Elite full-face, and MSA Ultra-Twin full-face. It is not compatible with MSA Advantage snap-on series facepieces, 3M bayonet facepieces, Moldex facepieces, or any other manufacturer's platform.

Can the MSA GMD-P100 be used in IDLH or oxygen-deficient atmospheres?

No. Like all air-purifying respirators (APRs), the MSA 815181 GMD-P100 requires an oxygen-sufficient atmosphere (≥19.5% O₂) and cannot be used in IDLH concentrations of any chemical. In oxygen-deficient or IDLH atmospheres, only a supplied-air respirator (SAR) or self-contained breathing apparatus (SCBA) is acceptable under OSHA 29 CFR 1910.134(d)(2).

How long does the MSA GMD-P100 cartridge last?

Service life depends on chemical concentration, humidity, work rate, and whether the limiting factor is the gas sorbent or the particulate filter. A written change-out schedule is required by OSHA 29 CFR 1910.134(d)(3)(iii) whenever the cartridge lacks an ESLI (which the GMD-P100 does not have). Some programs replace per shift for simplicity, but that practice still has to sit on top of a documented change schedule rather than replace one. Higher ammonia concentrations and elevated relative humidity (above 85%) both accelerate sorbent depletion and warrant shorter change-out intervals.

Is the MSA 815181 compatible with the MSA Advantage 200 LS half-mask?

The MSA Advantage 200 LS uses a distinct mounting system from the standard Advantage snap-on. Verify compatibility directly against the MSA product data sheet for the Advantage 200 LS before ordering GMD-P100 cartridges for it. The safe specification path is the Comfo Classic or Comfo II for confirmed GM bayonet compatibility.

MSA GMD-P100 vs MSA GME-P100 — which covers more?

The MSA 815182 GME-P100 covers nine gases — ammonia and methylamine plus chlorine, sulfur dioxide, chlorine dioxide, hydrogen chloride, hydrogen sulfide, hydrogen fluoride and formaldehyde (an organic compound, despite sitting in an otherwise inorganic list) — all with integrated P100 protection. It costs its listed price per cartridge versus its listed price for the GMD-P100. If there is any possibility of chlorine, H₂S, SO₂, or formaldehyde co-exposure, the GME-P100 is better value and broader protection. The GMD-P100 is only the better choice when the hazard assessment exclusively documents ammonia/methylamine with no other inorganic gas hazards — a narrower scenario than many buyers assume. Read the MSA GME-P100 review for the full breakdown.

What is the GTIN for the MSA 815181 GMD-P100?

The NIOSH Certified Equipment List is indexed by TC approval number, not by GTIN. or for procurement system data entry. The manufacturer SKU is 815181.

What does the "GMD" code mean in MSA's cartridge naming?

In MSA's GM-series naming convention, the letter suffix identifies the chemical sorbent type: A = organic vapor, B = acid gas, C = OV+acid gas, D = alkaline gas (ammonia/methylamine), E = multi-gas inorganic, T = multi-gas with tritium sorbent, I = radioiodine. The "-P100" suffix indicates an integrated P100 particulate filter. The MSA respirator filters and cartridges collection lists the full series.

Is there an MSA equivalent to the GMD-P100 for the Advantage platform?

The MSA Advantage GMD covers ammonia and methylamine on the Advantage snap-on platform, but it does not include an integrated P100 layer. There is no direct Advantage-platform equivalent to the GMD-P100 combination. For P100 particulate protection on the Advantage platform, a separate snap-on P100 filter would need to be evaluated against MSA's current Advantage accessory lineup. For combined alkaline gas + P100 on a single platform, the Comfo series with the 815181 remains the primary MSA offering.