MSA 815185 MERSORB Mercury Vapor / P100 Cartridge for Comfo Respirators — Box of 6

MSA MERSORB P100 Cartridge Overview

The MSA MERSORB Mercury Vapor / P100 Cartridge (SKU 815185) is a NIOSH-approved specialty combination cartridge that pairs MerSorb sorbent media — designed to capture odorless mercury vapor — with an integrated P100 particulate filter rated at 99.97% efficiency, sold in a box of 6 cartridges at $322.99 ($53.83 per cartridge). It threads onto the bayonet mount of MSA Comfo-series and GM-series full-face and half-mask respirators, making it the purpose-built answer when a hazard assessment confirms concurrent mercury vapor and fine particulate exposure.

Because mercury vapor produces no odor at dangerous concentrations, the MERSORB's sorbent chemistry — rather than a carbon bed alone — is engineered to adsorb elemental mercury without relying on sensory breakthrough as a change-out indicator. Pair that with end-of-service-life scheduling per OSHA 29 CFR 1910.134 and you have a defensible respiratory protection program for mercury-hazard environments.

Browse the full MSA Respirator Filters & Cartridges collection or use the respirator filter types guide if you are still evaluating which cartridge class applies to your hazard.

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Where the MSA MERSORB P100 Fits in Respirator Selection

Start with your hazard assessment. If air monitoring confirms elemental mercury vapor at concentrations above the OSHA PEL (0.1 mg/m³ ceiling) or the ACGIH TLV-TWA (0.025 mg/m³), and the atmosphere is NOT oxygen-deficient or IDLH, a supplied-air respirator or self-contained breathing apparatus is required instead. For exposures within the service concentration range established by your industrial hygienist, the MERSORB P100 is the correct APF-10 (half-mask) or APF-50 (full-face) combination-cartridge choice.

The P100 layer handles fine particulate — including mercury aerosol droplets and dusts — while the MerSorb media adsorbs gaseous elemental mercury and chlorine. If your hazard is organic vapor only, shift to the MSA GMA Organic Vapor cartridge. If your assessment adds acid gas to the matrix but no mercury, the MSA GMB Acid Gas cartridge or MSA GMC OV/Acid Gas cartridge are more appropriate and lower in cost. The filter types explainer walks through the full decision tree for combination cartridges.

Who Should Buy the MSA MERSORB P100?

Buy if:

• Your SDS or air-monitoring report identifies elemental mercury vapor as the primary inhalation hazard.
• You operate in a chlor-alkali plant, fluorescent lamp recycling facility, mercury-cell battery operation, dental amalgam preparation lab, or thermometer/instrument manufacturing environment where mercury exposure is documented.
• You already own an MSA Comfo Classic, Comfo II, Ultra-Twin, or Ultra-Elite full-face respirator with the standard GM-series bayonet thread mount.
• Your program requires concurrent P100 particulate protection (fine dust, aerosols, fume) alongside the vapor hazard.
• You need a chlorine gas emergency-response cartridge that also covers particulate — the MERSORB's sorbent chemistry handles both Hg and Cl₂.

Don't buy if:

• Your hazard is organic vapor without mercury — the MSA GMA P100 OV/Particulate cartridge costs significantly less and is the right tool.
• You need multi-gas coverage (OV + acid gas + ammonia) — use the MSA GME P100 Multi-Gas cartridge instead.
• Your respirator uses the MSA Advantage snap-on attachment system (200 LS, 290, 420) — those respirators require Advantage-series filters, not GM-series bayonet cartridges.
• You work in oxygen-deficient or IDLH conditions — air-purifying cartridges are never appropriate in those environments.

What Does the MSA MERSORB P100 Protect Against?

What the MSA MERSORB P100 Does NOT Protect Against

• Organic vapors (solvents, ketones, aldehydes) unrelated to mercury/chlorine chemistry
• Ammonia or amine gases — use the MSA GMD Ammonia/Methylamine cartridge for those hazards
• Methyl mercury or organomercury compounds (these require specific cartridge media beyond standard MerSorb; consult your IH)
• Carbon monoxide, hydrogen cyanide, or other IDLH-level gases
• Radioactive particulate — consult your radiation safety officer and applicable NRC requirements
• Biological hazards requiring N95/P100 with surgical resistance

Best Applications for the MSA MERSORB P100

Chlor-Alkali and Chemical Manufacturing

Mercury-cell chlor-alkali plants use elemental mercury as a cathode in the electrolytic production of chlorine and caustic soda. Maintenance and cell-room workers face concurrent mercury vapor and chlorine gas exposure — precisely the dual-hazard the MERSORB P100 was designed to address. Facility air-monitoring programs should establish ESLI or time-based change-out schedules since neither mercury vapor nor high chlorine concentrations provide reliable sensory warning at OSHA action levels. Review our guide to choosing the right respirator cartridge for program documentation requirements.

Dental Amalgam and Laboratory Mercury Handling

Dental operatories preparing or removing amalgam restorations, and research labs that handle liquid mercury, face chronic low-level mercury vapor release. The MERSORB P100's sorbent media is effective at the low concentrations typical of dental exposure when proper fit-testing is maintained on compatible MSA half-mask respirators. The P100 layer adds protection against amalgam dust and fine particulate generated during removal procedures.

Fluorescent Lamp Recycling and Mercury Recovery

Lamp recycling operations crush, sort, and process fluorescent tubes that contain mercury vapor. Workers at crushing stations, conveyors, and retort operations face peak mercury exposures that can rapidly exceed TLVs. The MERSORB P100 on a full-face respirator from the MSA full-face respirator collection provides an APF of 50, giving a 50-fold margin over the ambient concentration limit — critical in high-generation-rate tasks. Consult your filter selection guide for APF calculations.

Spill Response and Remediation

Environmental cleanup crews and facility emergency response teams handling mercury spills benefit from the MERSORB P100's combined vapor and aerosol protection. During vacuuming, amalgamation, or chemical treatment of spilled mercury, both elemental vapor and fine droplet aerosols are generated simultaneously. The combination cartridge eliminates the need to stack separate vapor and particulate media in emergency scenarios where setup time is limited.

MSA MERSORB P100 Pros and Cons

Compatible MSA Respirators

The MSA MERSORB P100 (815185) uses the GM-series threaded bayonet mount. It is compatible with the following respirators from the MSA full-face respirator collection and MSA half-mask respirator collection:

Always verify cartridge compatibility with your specific respirator model number before purchase. Consult MSA Safety's published compatibility documentation if your model is not listed above.

MSA MERSORB P100 vs Other MSA Filters and Cartridges

The table below compares GM-series bayonet cartridges from the MSA Respirator Filters & Cartridges collection to help you confirm the right selection for your hazard profile:

MSA MERSORB P100 vs MSA GMC P100 OV/Acid Gas Cartridge

The MSA GMC P100 OV/Acid Gas cartridge is the closest cross-hazard alternative in the GM-series lineup, offering combined organic vapor and acid gas protection with P100. Here is how the two compare for buyers evaluating chemical environments involving chlorine or acid gas exposure:

MSA MERSORB P100 vs MSA GME P100 Multi-Gas Cartridge

The MSA GME P100 Multi-Gas cartridge is the broadest-coverage option in the MSA GM-series lineup. If your hazard profile involves multiple chemical classes but your SDS does not specifically list mercury vapor, the GME P100 is often the more economical program choice:

MSA MERSORB P100 Quick Answers

What respirators does the MSA MERSORB P100 fit?

The MSA MERSORB P100 cartridge (SKU 815185) fits any MSA Comfo-series or GM-series respirator with the standard bayonet thread mount — including the Comfo Classic (Hycar and Silicone variants), Comfo II, Ultra-Twin, and Ultra-Elite full-face models. It does not fit the MSA Advantage-series respirators (200 LS, 290, 420), which use a different snap-on filter attachment system.

What is MerSorb and how is it different from activated carbon?

MerSorb is MSA's proprietary sorbent media specifically formulated to adsorb elemental mercury vapor through a chemical reaction with the sorbent surface, rather than simple physical adsorption used by activated carbon alone. Standard activated carbon cartridges — including MSA's own OV cartridges — are not NIOSH-approved for mercury vapor service because elemental mercury's vapor pressure and chemistry require a dedicated sorbent (typically gold-impregnated or iodine-impregnated carbon). MerSorb media meets NIOSH 42 CFR 84 requirements for mercury vapor service.

Does the MSA MERSORB P100 protect against organic vapors?

No. The MERSORB P100 cartridge is NIOSH-approved for mercury vapor, chlorine gas, and P100 particulate — it is not approved for organic vapor service. If your hazard assessment confirms both mercury vapor and organic solvents, consult your industrial hygienist. There is no single MSA GM-series cartridge that covers both mercury vapor and organic vapor in one body; separate respiratory protection strategies may be required.

How do I know when to change MSA MERSORB P100 cartridges?

Mercury vapor has no odor threshold that reliably warns the wearer before breakthrough at occupationally significant concentrations. OSHA 29 CFR 1910.134(d)(3)(iii) requires an objective change-out schedule when no reliable end-of-service-life indicator (ESLI) exists. Use your industrial hygienist's documented schedule based on measured air concentration, breathing rate, work duration, and manufacturer breakthrough data for the MERSORB media. Do not rely on smell or taste as a change-out signal for this cartridge.

Can I use the MSA MERSORB P100 cartridge on a half-mask for mercury exposure?

Yes, on compatible MSA Comfo-series half-mask respirators — but the assigned protection factor (APF) is 10, meaning the respirator reduces your exposure by a factor of 10 at most. If your measured mercury vapor concentration exceeds 10× the OSHA PEL or applicable OEL, a full-face respirator (APF 50) is required. Verify your fit-test results and air monitoring data before selecting half-mask versus full-face for your mercury control program.

Is the MSA MERSORB P100 sold individually or only in packs?

The MERSORB P100 (SKU 815185) is sold in boxes of 6 cartridges at $322.99 per box ($53.83 per cartridge). This pack size supports a typical industrial change-out schedule for multiple workers. Individual cartridge sales are not available for this specialty item through standard distribution channels.

How does the MSA MERSORB P100 compare to 3M mercury vapor cartridges?

Both MSA and 3M offer NIOSH-approved mercury vapor combination cartridges, but they use proprietary attachment systems that are not cross-compatible. The MSA MERSORB P100 uses MSA's GM-series bayonet mount and fits only MSA Comfo/GM-series respirators. 3M mercury cartridges use the 3M bayonet system and fit only compatible 3M half-mask and full-face respirators. See the 3M Respirator Filters & Cartridges collection if you are evaluating 3M platforms, and consult the OV vs P100 selection guide for framework comparison across brands.

MSA MERSORB P100 Specifications

Helpful Buying Guides

• How to Choose a Respirator Cartridge — Complete Selection Guide
• Respirator Filter Types Explained — N95, R95, P100, OV, AG and Combination
• Organic Vapor vs P100 — Which Filter Do You Actually Need?
• Respirator Cartridge Color Chart — NIOSH Color-Coding Explained
• Best Honeywell North Cartridge for Chlorine — Buyer's Guide
• Best Respirator for Welding Fumes — 2026 Buyer's Guide

MSA MERSORB P100 Frequently Asked Questions

Is the MSA MERSORB P100 cartridge reusable?

The cartridge body is designed for repeated use across multiple work shifts, but you must follow a documented change-out schedule based on your facility's air monitoring data and your industrial hygienist's determination of service life. Once the sorbent media is exhausted — even if the cartridge shows no visible damage — it must be replaced. Reusing a cartridge past its documented service life in a mercury environment is a serious respiratory protection failure.

Can the MSA MERSORB P100 be used for asbestos abatement?

The P100 layer provides the required 99.97% particulate filtration efficiency for asbestos fiber capture, but asbestos abatement has its own regulatory requirements under OSHA 29 CFR 1926.1101 and OSHA 1910.1001. A half-mask with P100 (APF 10) covers up to 1 f/cc under those standards. Verify that your respirator selection and program documentation meet all applicable asbestos abatement requirements before use — the MERSORB cartridge's mercury sorbent media adds no benefit for asbestos-only applications, so a standard MSA Low Profile P100 particulate filter may be more appropriate for asbestos-only applications.

What is the difference between a half-mask and full-face respirator for mercury vapor?

A half-mask respirator with the MERSORB P100 carries an assigned protection factor (APF) of 10 — it can be used where mercury vapor concentrations are no more than 10× the applicable OEL. A full-face respirator (such as the MSA Ultra-Twin or Ultra-Elite) with the same cartridge carries an APF of 50, allowing use at up to 50× the OEL. Full-face also protects the eyes and face from mercury vapor absorption through mucous membranes, making it the preferred choice for higher-risk tasks. Browse MSA full-face respirators or MSA half-mask respirators for compatible platforms.

Does the MSA MERSORB P100 protect against mercury chloride (mercuric chloride) vapor?

The MERSORB P100 is NIOSH-approved for elemental mercury vapor (Hg⁰) and chlorine gas. Inorganic mercury compounds such as mercuric chloride (HgCl₂) have different vapor pressures and toxicological profiles than elemental mercury. Consult your industrial hygienist and review the NIOSH approval documentation for the specific compound in your workplace before relying on this cartridge for inorganic mercury compound vapors. Do not extrapolate from the elemental mercury approval without verified data.

How many cartridges do I need for a full-face respirator?

Full-face MSA GM-series respirators such as the Ultra-Twin and Ultra-Elite use two cartridges simultaneously — one on each side of the face piece. A box of 6 MERSORB P100 cartridges therefore provides 3 complete change-out sets for a single full-face respirator. For a fleet of multiple full-face respirators or frequent change-out schedules, plan your order quantities accordingly.

Is the MSA MERSORB P100 approved for use in dental offices?

The cartridge's NIOSH approval for mercury vapor makes it technically suitable for dental amalgam exposure scenarios from a filtration standpoint, provided the respirator achieves an adequate seal via fit testing and the change-out schedule accounts for low-concentration dental exposure conditions. However, dental-specific respiratory protection programs should be designed with input from an industrial hygienist familiar with the OSHA Mercury in Dental Offices standard and applicable state dental board regulations. NIOSH approval alone does not constitute a complete respiratory protection program.

Can I mix MSA MERSORB P100 cartridges with cartridges from other brands on the same respirator?

No. Mixing cartridges from different manufacturers on the same respirator is not permitted — it compromises the NIOSH approval of the respirator-cartridge combination and may void fit-test validation. Only use MSA GM-series cartridges on compatible MSA GM-series respirators, and only use approved cartridges from the same manufacturer and series on both sides of a dual-cartridge face piece.

What personal protective equipment should I pair with the MSA MERSORB P100 for mercury spill response?

Respiratory protection is one component of a mercury spill response program. Pair the MERSORB P100 respirator with impervious chemical protective gloves (butyl or neoprene rubber), eye and face protection on half-mask configurations, chemical-resistant coveralls or aprons, and appropriate footwear covers. Mercury can be absorbed through the skin at high concentrations — respiratory protection alone is insufficient for spill response tasks. Consult your facility's written mercury spill response plan and applicable regulatory guidance from OSHA and EPA.

How should I store unused MSA MERSORB P100 cartridges?

Store unused MERSORB P100 cartridges in their original sealed packaging in a cool, dry location away from direct sunlight, strong oxidizers, and chemical vapors. Sorbent media can degrade or pre-load if exposed to ambient chemical vapors even before first use. Follow MSA Safety's published storage guidelines and observe the shelf-life expiration date printed on the packaging. Do not use cartridges from damaged or previously opened packaging for regulated mercury vapor service.

Does the MSA MERSORB P100 require additional pre-filters?

No separate pre-filter is required. The MERSORB P100 integrates a P100 particulate layer within the cartridge body, providing both particulate and vapor protection in a single unit. Adding an additional pre-filter is not supported by the NIOSH approval for this cartridge configuration and could increase breathing resistance beyond tested parameters.

What NIOSH color coding applies to mercury vapor cartridges?

Under NIOSH color-coding guidelines, purple (magenta) indicates P100 particulate filtration. Mercury vapor and chlorine cartridges carry an olive/green body color per NIOSH 42 CFR 84 coding conventions for specialty vapor cartridges. A combination mercury vapor + P100 cartridge such as the MERSORB P100 may display both color indicators. The respirator cartridge color chart guide explains the full NIOSH color-coding system for all cartridge types.

Is there a Moldex or 3M equivalent to the MSA MERSORB P100?

Both 3M and Honeywell North offer NIOSH-approved mercury vapor combination cartridges for their respective respirator platforms — but none are cross-compatible with MSA GM-series respirators. If you are evaluating alternatives for a non-MSA respirator platform, browse the 3M Respirator Filters & Cartridges or Moldex Respirator Cartridges & Filters collections. Cartridge attachment systems are brand-specific and not interchangeable.

Where can I find a full comparison of MSA cartridges for my hazard profile?

The respirator cartridge selection guide covers hazard-by-hazard cartridge matching for all major NIOSH-approved categories. For a visual reference covering OV, P100, combination, and specialty canisters, see the respirator filter types explainer. For MSA-specific cartridges, browse the complete MSA Respirator Filters & Cartridges collection.