MSA 464032 GMB Acid Gas Cartridge for Comfo Respirators — Box of 10

MSA GMB Acid Gas Cartridge Overview

The MSA GMB (SKU 464032) is a NIOSH-approved acid gas cartridge designed exclusively for the threaded bayonet mount used on the MSA Comfo-series respirator platform, sold in a box of 10 cartridges at $147.64 — $14.76 per cartridge. It uses an impregnated activated carbon sorbent bed formulated to capture and neutralize acidic vapor species including chlorine (Cl₂), sulfur dioxide (SO₂), hydrogen chloride (HCl), hydrogen fluoride (HF), and hydrogen sulfide (H₂S). Buyers selecting cartridges for MSA full-face respirators or the Comfo half-mask should first consult the respirator cartridge selection guide and the respirator filter types explainer to confirm hazard class match. The GMB carries no particulate rating and provides no organic vapor protection — where either is needed, see the MSA GMB P100 combination cartridge.

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Where the MSA GMB Fits in Respirator Selection

Respiratory protection decisions begin by identifying the hazard class. If your industrial hygiene assessment confirms acid gas exposure — and only acid gas — with no concurrent particulate or organic vapor hazard, the GMB is the right cartridge. It is classified as an Air-Purifying Respirator (APR) cartridge with an Assigned Protection Factor (APF) of 10 per OSHA 29 CFR 1910.134, appropriate for atmospheres up to 10 times the permissible exposure limit when worn with a properly fit-tested half-mask. Full-face respirators raise that APF to 50.

If your SDS or air monitoring shows mixed hazards — acid gas alongside organic vapors or dust — review the organic vapor vs. P100 comparison and the NIOSH cartridge color-code chart before ordering. Selecting the wrong cartridge in a multi-hazard environment is a compliance failure and a serious safety risk. The full MSA cartridge and filter lineup includes combination cartridges for mixed-hazard applications.

Who Should Buy the MSA GMB?

Buy the GMB if:

• You already own or are purchasing an MSA Comfo Classic, Comfo II, Ultra-Twin, or Ultra-Elite full-face respirator — the bayonet mount is required.
• Your air monitoring confirms acid gas hazards (Cl₂, SO₂, HCl, HF, H₂S) with no particulate co-exposure.
• You're replacing cartridges on a scheduled change-out interval and want to maintain a pure acid gas cartridge without paying for P100 media you don't need.
• You're stocking a maintenance facility, water treatment plant, semiconductor fab, or pulp-and-paper operation where acid gas is the primary atmospheric hazard.

Do not buy the GMB if:

• Your environment has dust, fumes, or mists — choose the MSA GMB P100 combination cartridge instead.
• You need organic vapor coverage — the MSA GMC OV/Acid Gas cartridge or MSA GMC P100 combination cartridge covers both hazard classes.
• Your respirator uses the MSA Advantage bayonet (thread-type snap-on) rather than the Comfo threaded bayonet — compatibility does not cross between these two MSA connection systems.
• You need ammonia or methylamine protection — see the MSA GMD Ammonia/Methylamine cartridge.

What Does the MSA GMB Protect Against?

The table below lists each hazard the GMB is rated for, its NIOSH-assigned coverage status, and buyer guidance per hazard.

What the MSA GMB Does NOT Protect Against

• Particulates — no filter media; dust, welding fumes, and mists pass through unimpeded.
• Organic vapors — solvents, fuels, and volatile organics are not captured by the acid gas sorbent.
• Ammonia and amines — alkaline gases require a separate sorbent formulation.
• Radioactive particulates and iodine — use the MSA GMI Iodine/P100 cartridge for iodine hazards.
• Mercury vapor — use the MSA Mersorb P100 Mercury Vapor cartridge.

Best Applications for the MSA GMB Acid Gas Cartridge

Water Treatment and Chlorination Facilities

Operators managing chlorine gas injection systems, sodium hypochlorite handling, or on-site chlorine generation face direct Cl₂ and HCl exposure risk. The GMB provides the acid gas protection needed during routine maintenance, chemical dosing, and emergency response without the added cost of P100 filtration when particulate hazard is absent. See the full MSA respiratory protection lineup for complementary PPE.

Semiconductor and Electronics Manufacturing

Fab environments routinely use HF, HCl, and other acid gases in etching and cleaning processes. The GMB's HF coverage makes it a direct fit for cleanroom-adjacent maintenance tasks where particulate exposure is controlled through facility engineering. Pair with a compatible MSA full-face respirator for eye protection in acid gas environments.

Pulp, Paper, and Sulfite Processing

Sulfur dioxide is a persistent byproduct in kraft and sulfite pulping operations. Maintenance workers entering digester areas, chemical recovery, or acid plant zones need reliable SO₂ protection. The GMB's NIOSH SO₂ rating covers this application when atmospheric monitoring confirms acid gas as the primary hazard.

Oil, Gas, and Wastewater H₂S Exposure

H₂S is present at wastewater lift stations, anaerobic digesters, and oil-and-gas production facilities. Workers performing inspection or maintenance tasks in H₂S-monitored below-IDLH atmospheres use the GMB as their primary cartridge. Review the cartridge selection guide to confirm atmosphere concentration is within APR limits before relying on any cartridge in H₂S service.

MSA GMB Pros and Cons

Compatible MSA Respirators

The GMB uses a threaded bayonet mount specific to the MSA Comfo/GM-series platform. The table below lists confirmed compatible and incompatible respirators.

Always verify the cartridge mount type against your specific respirator model before purchase. For MSA Advantage-series filters, see the MSA Advantage P100 filter and related Advantage accessories.

MSA GMB vs. Other MSA GM-Series Cartridges

All cartridges below share the threaded bayonet mount and fit the same Comfo/GM-series respirators. Select based on your confirmed hazard profile.

MSA GMB vs. MSA GMB P100 — Acid Gas Only vs. Combination

MSA GMB vs. MSA GMC — Acid Gas Only vs. OV/Acid Gas

MSA GMB Quick Answers

Does the MSA GMB filter particulates?

No. The GMB is an acid gas-only cartridge with no filter media. It provides zero protection against dust, fumes, aerosols, or mists. Environments with both acid gas and particulate hazards require the MSA GMB P100 combination cartridge, which pairs the same acid gas sorbent with a P100 filter layer.

What respirators does the MSA GMB fit?

The GMB uses MSA's threaded bayonet mount and fits the Comfo Classic, Comfo II, Ultra-Twin, and Ultra-Elite respirators. It does not fit MSA Advantage-series respirators, which use a different snap-on connection system. Always cross-reference the mount type on your specific respirator before purchasing.

How long does the MSA GMB last per use?

Service life is not fixed. It depends on the concentration of the acid gas, temperature, relative humidity, and the wearer's breathing rate. MSA does not publish a guaranteed service life in hours. Users are required to establish a change-out schedule based on OSHA's cartridge change-out schedule guidelines, employer industrial hygiene data, or a published service life model for the specific chemical. The GMB contains no end-of-service life indicator (ESLI).

Is the MSA GMB approved for hydrogen fluoride?

Yes. The GMB carries NIOSH approval covering hydrogen fluoride (HF) as part of its acid gas rating. HF is particularly relevant in semiconductor manufacturing and aluminum smelting environments. Verify concentration levels are within APR-permissible limits before relying on any cartridge for HF service.

Can the MSA GMB be used for hydrogen sulfide (H₂S)?

Yes, for below-IDLH concentrations where atmospheric monitoring has confirmed the H₂S level is within the APR's protective range. The IDLH for H₂S is 50 ppm (NIOSH). Atmospheres at or above IDLH, or where H₂S concentration is unknown, require supplied-air or SCBA equipment — not an air-purifying cartridge.

Can I add a prefilter to the MSA GMB for dual protection?

No. The GMB itself has no attachment point for a particulate prefilter. The Comfo-series system addresses combined protection through combination cartridges — specifically the GMB P100, which integrates both sorbent and filter media into a single unit. The MSA Advantage platform's snap-on prefilter accessories are not compatible with Comfo-series cartridges.

How does the MSA GMB compare to the 3M 6002 Acid Gas cartridge?

Both are NIOSH-approved acid gas cartridges for their respective platforms. The GMB is exclusively for MSA Comfo-series respirators; the 3M 6002 fits 3M 6000/7000 series respirators. They are not interchangeable. If you own an MSA Comfo-series respirator, the GMB is your correct cartridge. Review the filter types guide for cross-brand selection context.

MSA GMB Acid Gas Cartridge Specifications

Helpful Buying Guides

• How to Choose a Respirator Cartridge — Complete Selection Guide
• Respirator Filter Types Explained — OV, AG, P100, Combination
• NIOSH Respirator Cartridge Color Code Chart
• Organic Vapor vs. P100 — Which Filter Do You Need?
• Best Respirator Cartridge for Chlorine — Brand Comparison Guide
• Shop All MSA Respirator Filters and Cartridges
• MSA Half-Mask Respirators

MSA GMB Acid Gas Cartridge Frequently Asked Questions

Does the MSA GMB work on the MSA Comfo half-mask respirator?

Yes. The GMB is specifically designed for the threaded bayonet connection on all Comfo-series half-mask respirators including the Comfo Classic and Comfo II. It installs by inserting and rotating into the cartridge port and does not require tools.

Can I use the MSA GMB on an MSA Advantage respirator?

No. MSA Advantage-series respirators use a snap-on bayonet connection that is not compatible with the Comfo threaded bayonet mount on the GMB. Forcing the wrong cartridge creates a face-seal leak and eliminates respiratory protection. Confirm your respirator model before ordering.

How many cartridges are in a box of MSA GMB?

Each box contains 10 cartridges at a total price of $147.64, which equals $14.76 per individual cartridge. For users with multiple respirators or high-frequency change-out schedules, the 10-pack pricing provides a per-unit cost advantage over single-cartridge purchasing.

What is the shelf life of an unopened MSA GMB cartridge?

MSA recommends storing cartridges in the original sealed packaging in a cool, dry environment away from contaminants. Refer to the lot number and manufacture date on the packaging for specific shelf life guidance, and follow your employer's respiratory protection program for storage and inspection procedures.

Does the GMB protect against chlorine gas at water treatment facilities?

Yes. Chlorine (Cl₂) is one of the named hazards on the GMB's NIOSH approval. Water treatment workers managing chlorine injection or gas cylinder changeouts within below-IDLH atmospheric concentrations can use the GMB as their primary respiratory protection when worn with a properly fit-tested Comfo-series respirator.

Is a fit test required when using the MSA GMB?

Yes. OSHA 29 CFR 1910.134 requires annual quantitative or qualitative fit testing for all tight-fitting respirators, including the Comfo half-mask and full-face units. The cartridge's NIOSH approval and APF rating assume a properly fit-tested respirator. An untested or poorly fitted respirator negates the cartridge's protection regardless of NIOSH approval.

What is the NIOSH color code for the MSA GMB?

Acid gas cartridges carry a green label per the NIOSH color-coding system. This applies to the GMB as a pure acid gas cartridge. The NIOSH cartridge color chart guide explains all color codes and how to read combination labels.

Do I need to replace both cartridges at the same time on a dual-cartridge respirator?

Yes. On dual-cartridge full-face respirators like the Ultra-Twin, both cartridges should be replaced at the same time on the same schedule. Replacing one cartridge while leaving the other increases the risk of uneven service life and potential breakthrough on the older side.

Can the MSA GMB be used in an atmosphere where both acid gases and organic vapors are present?

No. The GMB's sorbent is formulated for acid gases only and provides no organic vapor protection. If your hazard assessment identifies both acid gas and organic vapor co-exposure, you need the MSA GMC OV/Acid Gas cartridge, which contains both sorbent types. Using the wrong cartridge is a regulatory violation and a direct safety risk.

Is the MSA GMB suitable for emergency response applications?

Air-purifying respirators including the GMB are not suitable for emergency response entry into unknown or IDLH atmospheres. Emergency response to chemical spills, confined-space rescues, or any scenario where atmospheric concentration is unknown or may exceed IDLH requires SCBA. The GMB is appropriate for routine maintenance and operational tasks where air monitoring has confirmed below-IDLH concentrations.

Where can I buy replacement MSA GMB cartridges?

The MSA GMB (464032) is available in a 10-pack at WC Safety and through authorized MSA distributors. You can also purchase through the Amazon listing above. Purchasing from authorized retailers ensures you receive genuine MSA cartridges with current lot numbers, proper packaging, and manufacturer warranty coverage.

Does the MSA GMB have an odor warning property for the gases it protects against?

Odor warning properties vary by gas. Chlorine and H₂S have detectable odors at low concentrations, which may provide a sensory cue. However, odor alone is not a reliable indicator of cartridge saturation — olfactory fatigue, individual variation, and the absence of odor at breakthrough for some chemicals make odor-based change-out unreliable. Always use a documented change-out schedule.