Respirator Filters & Cartridges Guide: Selection by Hazard Type (2026)

Respirator Filters & Cartridges: Selection by Hazard Type

Choosing the wrong cartridge is not a minor error — an organic vapor cartridge provides zero protection against ammonia, and a P100 filter provides zero protection against chemical vapors. NIOSH 42 CFR Part 84 defines the filter classes, but matching those classes to your specific workplace hazard is the buyer's responsibility. This guide covers every major cartridge type, by-hazard selection, and brand options from the 3M cartridge collection, Moldex cartridge collection, and Honeywell North cartridge collection.

Quick picks: Organic vapor only → 3M 6001 OV. Particulate only → 3M 2091 P100. OV + particulate → 3M 60921 OV/P100. Multi-hazard → 3M 60926 MGVP/P100. For the step-by-step selection process, see how to choose a respirator cartridge.

NIOSH Filter Classes: P100, N95, R95, N100 Explained

NIOSH 42 CFR Part 84 assigns filter classes based on two criteria: (1) oil-resistance — N (Not oil-resistant), R (oil-Resistant, 8 hours max), P (oil-Proof, no time limit); (2) filter efficiency — 95 (≥95%), 99 (≥99%), 100 (≥99.97%). All classes are tested against 0.3 micron particles, which are the most penetrating aerosol size.

For industrial applications involving any oil-based hazard, P100 is the default choice. See the P100 vs N100 vs N95 guide and P100 respirator filter collection.

Cartridge Types: Gas/Vapor vs Particulate vs Combination

Particulate Filters (P100, N95, R95)

Particulate filters are mechanical — they capture particles physically without chemical interaction. They protect against dust, fume, mist, aerosols, and biological particles. They provide NO protection against gas or vapor hazards. Top picks: 3M 2091 P100 (standalone filter), 3M 7093 P100 cartridge, Moldex 7740 P100, North 7580 P100.

Gas/Vapor Cartridges (OV, AG, AM, MGVP)

Gas/vapor cartridges contain sorbent media (typically activated carbon) that chemically adsorbs gas and vapor molecules. They provide NO particulate protection unless a P100 filter disc or combination filter is added. Key types: Organic Vapor (OV), Acid Gas (AG), Ammonia/Methylamine (AM), Multi-Gas/Vapor (MGVP). Top picks: 3M 6001 OV, 3M 6003 OV/AG, 3M 6006 MGVP, Moldex 7100 OV.

Combination Cartridges (Gas + P100)

Combination cartridges combine a gas/vapor sorbent layer with an integrated P100 particulate filter — no separate filter disc needed. The most versatile option for environments with both gas and particulate hazards. When to use combination vs separate guide. Examples: 3M 60921 OV/P100, 3M 60923 AG/OV/P100, 3M 60926 MGVP/P100, Moldex 7667 MGVP/P100 Smart.

Select by Hazard Type

Always consult the chemical SDS (Safety Data Sheet) for the specific contaminant, concentration, and recommended respiratory protection before selecting a cartridge. See OSHA 1910.134 respiratory protection standard for the written respiratory protection program requirement.

Combination Cartridges: P100 + Gas/Vapor

Most industrial environments with chemical hazards also have particulate hazards (fume, mist, dust). Combination cartridges eliminate the need to manage separate cartridge and filter components. The 3M 60923 OV/AG/P100 and North 7583P100L OV/AG/P100 are the most specified combination cartridges for environments with both organic vapor/acid gas and particulate hazards.

When to use stand-alone gas cartridge + separate filter: when you already have gas cartridges and need to add particulate filtration; when you need to swap between cartridge types without replacing both components. See combination vs separate filter guide and OV vs OV/AG vs multi-gas guide.

3M vs Moldex vs Honeywell North Cartridge Comparison

See brand-specific selection resources: Best Honeywell North cartridges, Best Moldex cartridges, Honeywell North cartridge guide.

Cross-brand comparison guides: Moldex 7100 vs 3M 6001 OV comparison, Moldex 7600 vs 3M 6006 MGVP comparison, North 7583P100L vs 3M 60923, Moldex 7740+ vs 3M 2091 P100 comparison.

Cartridge Change Schedule and Service Life

OSHA 1910.134(d)(3)(iii) requires that cartridges be replaced before the end of their service life. Two acceptable methods:

• ESLI (End-of-Service-Life Indicator): color-change indicator built into the cartridge signals when to change. Available on Moldex Smart Cartridges (7600, 7607, 7667). The ESLI turns from yellow to dark blue when the sorbent is saturated.
• Written change schedule: employer establishes change frequency based on contaminant concentration, cartridge capacity, and daily exposure hours. Required when ESLI-equipped cartridges are not used. See ESLI vs written change schedule guide.

P100 particulate filters do not have a defined chemical service life — replace when breathing resistance increases noticeably, when physically damaged, or when contaminated. See how long do respirator cartridges last for the full breakdown.

Respirator Filters & Cartridges: Frequently Asked Questions

What is the difference between a respirator filter and a cartridge?

A filter is a mechanical device that removes particulate matter (dust, mist, fume) from air by physical capture. A cartridge contains sorbent material (activated carbon or other chemical media) that adsorbs gas and vapor molecules. Combination cartridges include both a sorbent cartridge layer and an attached particulate filter — the 3M 60921 (OV+P100) is an example. Stand-alone filters like the 3M 2091 P100 only remove particles; they do not protect against gas or vapor hazards.

What does P100 mean on a respirator filter?

P100 is a NIOSH filter class per 42 CFR Part 84. "P" = oil-proof (can be used in both oil and non-oil mist environments, no time restriction). "100" = ≥99.97% filter efficiency. A P100 filter removes at least 99.97% of particles 0.3 microns in diameter. Compare to N95 (not oil-resistant, ≥95% efficiency) and R95 (oil-resistant for up to 8 hours/one shift, ≥95% efficiency). See the full P100 vs N100 vs N95 guide.

What respirator cartridge do I need for organic vapors?

Organic vapor (OV) cartridges use activated carbon to adsorb hydrocarbon vapors. For particulate hazards alongside organic vapors, use a combination OV/P100 cartridge: 3M 60921 OV/P100, North 7581P100L OV/P100, or Moldex 7300 OV/AG. See the organic vapor vs P100 guide for when OV alone is sufficient versus when OV+P100 is required.

What cartridge do I need for acid gas (HCl, H2SO4, SO2)?

Acid gas cartridges use specific chemical sorbents (alumina-based media) rated for acidic gas molecules. NIOSH filter class: Acid Gas. For combination protection, use OV/AG or P100/AG: 3M 6003 OV/AG, 3M 60923 P100/OV/AG, North 7582P100L AG/P100. See the best cartridge for acid gas guide.

What cartridge do I need for ammonia or methylamine?

Ammonia and methylamine require a specific ammonia/methylamine (AM) cartridge — standard organic vapor cartridges do NOT protect against ammonia. Options: North 75SCL Defender multi-gas (covers ammonia + other inorganic gases), North 75SCP100L multi-contaminant P100. See the best cartridge for ammonia guide.

What is a multi-gas/vapor (MGVP) cartridge?

A multi-gas/vapor cartridge combines multiple sorbent layers to protect against a broader range of chemical hazards in a single cartridge: organic vapors, acid gases, inorganic gases (ammonia, chlorine), and often P100 particulate filtration. Examples: 3M 6006 MGVP, 3M 60926 MGVP/P100, North 75SCP100L, Moldex 7600 Smart multi-gas. Use when multiple chemical hazards are present and a single cartridge is preferred over stacking separate media.

How do respirator cartridge color codes work?

NIOSH assigns color codes to indicate the type of protection a cartridge provides, standardized per ANSI Z88.7. Key codes: Black = Organic Vapor; White = Acid Gas; Green = Ammonia/Methylamine; Yellow = OV+AG combination; Purple (Magenta) = P100 particulate; Olive = Multi-gas/vapor. Color codes are printed on the cartridge body and packaging. See the respirator cartridge color codes reference for the complete NIOSH color-code chart.

Are respirator cartridges universal across brands?

No — cartridge mounts are proprietary and brand-specific. 3M cartridges fit only 3M respirators (bayonet-style); Moldex cartridges fit only Moldex 7000/9000 series; Honeywell North cartridges fit only North 5500/7700/5400/7600 series. Never use a cartridge from one brand on a respirator from another — the mount may appear to engage but the seal will be compromised. See the cartridge selection guide for brand-to-respirator compatibility.

What is NIOSH 42 CFR Part 84?

42 CFR Part 84 is the federal regulation governing NIOSH approval of air-purifying respirators and filter/cartridge devices. It establishes performance requirements for each filter class (N, R, P in 95/99/100 efficiency levels), approval testing procedures, and labeling requirements. All NIOSH-certified cartridges and filters display the TC (Testing and Certification) approval number on the packaging. See the NIOSH Certified Equipment List to verify approval status.

When should I use a P100 filter instead of an N95?

P100 filters (≥99.97% efficiency, oil-proof) are required when: (1) oil mists or metal working fluids are present (N95 and N100 cannot be used in oil environments); (2) maximum particulate protection is needed (P100 vs N95 = 99.97% vs 95%); (3) the contaminant is highly toxic or carcinogenic (silica, asbestos, lead, beryllium). N95 is appropriate for dry particulate environments (wood dust, non-oily metal dust, biological aerosols) where 95% efficiency is OSHA-compliant. See P100 vs N95 guide.

How do I know when to replace a respirator cartridge?

There are two acceptable methods per OSHA 1910.134: (1) End-of-service-life indicator (ESLI) — for cartridges with a color-change indicator (Moldex Smart Cartridges 7600/7607/7667); (2) Written change schedule — employer establishes a change frequency based on contaminant concentration, cartridge capacity, and exposure time. P100 filters are replaced when breathing resistance increases noticeably or when physically damaged. See how long do respirator cartridges last and ESLI vs written change schedule guide.

What cartridge do I need for formaldehyde?

Formaldehyde requires a formaldehyde-specific cartridge or a multi-gas cartridge rated for formaldehyde. Standard organic vapor cartridges have limited formaldehyde capacity and may not provide adequate protection at occupational exposure levels. See the best cartridge for formaldehyde guide for verified options. Always verify against the chemical SDS for the specific formaldehyde concentration.

Can I use the same cartridge for welding fumes?

Welding fumes are primarily metallic particulate (requiring P100 filter) with possible gas/vapor components depending on the process and materials (OV, nitrogen dioxide, ozone). For most welding processes: 3M 7093 P100 cartridge, Moldex 7740 P100 filter, or a combination cartridge if gas hazards are also present. See the cartridge selection guide for welding-specific hazard matching.

What is the difference between OV, AG, and MGVP cartridges?

OV (organic vapor) = activated carbon cartridge rated for hydrocarbons; AG (acid gas) = chemical media rated for acidic gases (HCl, SO2, H2S); MGVP (multi-gas/vapor) = combined media covering OV + AG + inorganic gases. OV+AG combination covers more hazards than OV alone but less than MGVP. See the OV vs OV/AG vs multi-gas guide and combination cartridge vs separate filter guide for decision criteria.

Do I need a separate filter for particulates when using a gas cartridge?

If your hazard includes both gas/vapor AND particulate contaminants, you have two options: (1) Use a combination cartridge that includes P100 filtration (e.g., 3M 60921 OV/P100 or North 7583P100L OV/AG/P100); or (2) Add a P100 filter disc to a gas cartridge on compatible platforms. Option 1 is cleaner. Option 2 is appropriate if you already have gas cartridges and want to add particulate protection. See combination cartridge vs separate filter guide.