Not all chemical-resistant gloves resist the same chemicals, and a glove that looks fine after use is not necessarily still protective. This guide is a companion to CASRAI’s PPE Selection for Chemical Handling in the Lab, which covers the overall logic of glove, eyewear, and lab-coat selection but deliberately stops short of a detailed chemical-to-material comparison. Here we go deeper: how glove failure actually happens, what the numbers on a manufacturer’s chemical-resistance chart mean, how common glove materials compare against common lab chemical classes, and how to build a defensible change-out schedule.
Three Ways a Glove Fails — And Why Only One Is Invisible
Under OSHA’s PPE standard for hand protection, 29 CFR 1910.138, employers must select gloves based on the specific task, the hazards present, and the glove material’s performance against those hazards — not a single all-purpose glove for the whole lab. For chemical handling, “chemical-resistant” breaks into three distinct failure modes:
- Degradation — the glove material physically changes on contact with a chemical: swelling, softening, hardening, cracking, or dissolving. Degradation is usually visible, which is exactly why it is the least dangerous failure mode — you can see it and react.
- Penetration — bulk liquid passes through a pinhole, tear, seam, or other physical defect in the glove. This is a manufacturing/damage issue, not a material-chemistry issue, and standard pre-use inspection (stretch, look for pinholes, check seams) catches most of it.
- Permeation — the chemical moves through the glove material at a molecular level, without any visible sign of damage. This is the dangerous one: a glove can look and feel completely intact while chemical is already passing through it into contact with skin.
How Permeation Is Actually Measured: ASTM F739 and Breakthrough Time
Permeation resistance is measured under ASTM F739, the standard test method for measuring chemical permeation through protective clothing materials. In the test, one side of a glove material sample is exposed to the challenge chemical while a detector on the other side monitors for the chemical crossing through. The key result is breakthrough time — commonly reported as the standardized breakthrough time (SBT), the point at which the permeation rate reaches a defined threshold (100 ng/cm²/min under the current standardized method). Once breakthrough time has elapsed, the glove is considered to have failed for that chemical, even if it still looks and feels fine.
The ANSI/ISEA 105 standard (American National Standard for Hand Protection Classification) translates raw breakthrough-time data into a simple 0–6 chemical permeation resistance class that appears on many U.S. glove charts and packaging:
| ANSI/ISEA 105 Class | Breakthrough Time |
|---|---|
| Class 0 | Less than 10 minutes |
| Class 1 | ≥ 10 minutes |
| Class 2 | ≥ 30 minutes |
| Class 3 | ≥ 60 minutes |
| Class 4 | ≥ 120 minutes (2 hours) |
| Class 5 | ≥ 240 minutes (4 hours) |
| Class 6 | ≥ 480 minutes (8 hours) |
A higher class number means longer protection against that specific chemical, at that specific concentration and temperature — the same glove can rate Class 6 against one chemical and Class 0 against another. Labs outside the U.S., or working with equipment/PPE sourced internationally, will also encounter EN 374, the European standard for protective gloves against chemicals and micro-organisms, which uses its own breakthrough-time-based classification and a letter code (Type A, B, or C) indicating how many standard test chemicals a glove resists for at least 30 minutes. The underlying physics — degradation, penetration, permeation, and breakthrough time — is the same across both standards; only the labeling convention differs.
Reading a Manufacturer’s Glove Chart
Ansell, Honeywell/North, MAPA, Kimberly-Clark, and other glove manufacturers publish free online chemical-resistance charts that list, for each glove product, a rating (often the ANSI/ISEA 0–6 class, or a manufacturer-specific letter grade) against a long list of individual chemicals. To use one correctly:
- Match the exact chemical, not the category. “Acid” is not a chemical — sulfuric acid and acetic acid behave very differently against the same glove material. Look up the specific compound.
- Match the concentration. A glove rated well against a dilute acid solution can fail quickly against the concentrated form of the same acid. Charts that don’t specify concentration should be treated as a rough starting point, not a final answer.
- Match the glove product, not just the material. “Nitrile” is a material family, not a single product — a 4-mil disposable nitrile exam glove and a 15-mil unsupported nitrile chemical glove are built from related but not identical formulations, at very different thicknesses, and will have meaningfully different breakthrough times against the same chemical. Look up the specific product line, not the generic material name.
- Check the mixture, not just each component. Charts rate single chemicals. A glove that resists two chemicals individually may not resist a mixture of the two as well as the weaker-performing chemical alone — for genuinely novel or unusual mixtures, the safe default is to treat the mixture as the worst-case single component, or test/verify with the manufacturer.
Because different manufacturers formulate their materials differently, publish charts in different formats, and test against different chemical lists, this guide does not reproduce any single manufacturer’s chart as authoritative — always confirm against the current chart for the specific glove product in use, and cross-check against Section 8 (Exposure Controls/Personal Protection) of the chemical’s Safety Data Sheet, which frequently specifies a recommended glove material directly.
Glove Material Comparison: General Resistance by Chemical Class
The table below summarizes typical resistance patterns for the glove materials most commonly stocked in research labs, against broad chemical classes. Treat every cell as a starting point for further lookup, not a final answer — always verify against a current manufacturer chart for the specific chemical, concentration, and glove product before relying on it.
| Glove Material | Ketones (acetone, MEK) | Alcohols | Chlorinated Solvents | Strong Acids | Strong Bases | Aromatic Hydrocarbons (toluene, benzene) | Typical Lab Role |
|---|---|---|---|---|---|---|---|
| Nitrile | Poor | Good | Fair–Poor | Fair–Good | Good | Fair–Poor | General bench default; biological work |
| Natural rubber latex | Poor | Fair | Poor | Fair | Fair–Good | Poor | Largely phased out for chemical work — allergy risk, weak solvent resistance |
| Neoprene | Fair | Good | Fair | Good | Good | Fair | Broader all-around resistance than nitrile when nitrile is inadequate |
| Butyl rubber | Excellent | Good | Fair–Poor | Good | Good | Poor | Aggressive ketones, esters, and gas/vapor permeation resistance |
| PVC (vinyl) | Poor | Fair | Poor | Good | Good | Poor | Aqueous acids/bases, low-cost general handling |
| Viton (fluoroelastomer) | Fair | Good | Excellent | Good | Fair | Excellent | Aggressive chlorinated and aromatic organic solvents |
| Laminate barrier film (e.g., multi-layer PE/EVOH laminates) | Excellent | Excellent | Excellent | Excellent | Excellent | Excellent | Most aggressive/exotic chemicals; poor mechanical strength, worn as an inner glove under a sturdier outer glove |
No single material is a universal answer. Nitrile is a sound default for general bench work and biological fluids but is a poor choice against acetone and many other polar solvents — one of the most common glove-selection mistakes is assuming any nitrile glove is safe for any organic solvent because it is the lab’s everyday glove. When a task involves a chemical that a given material rates poorly against, the correct response is to switch materials or double-glove, not to keep using the familiar glove for convenience.
Thickness and “Mil” Rating
Glove thickness is commonly expressed in mils (1 mil = 0.001 inch, or 0.0254 mm). Disposable exam-style gloves are typically in the 3–8 mil range and are designed for barrier protection against biological fluids and light contamination, not sustained chemical contact. Dedicated chemical-handling gloves — supported or unsupported — commonly run 11–25+ mils and are formulated and tested specifically for longer breakthrough times against the chemicals in their published chart. Thickness alone does not determine resistance (material chemistry matters more), but for a given material, thicker generally means a longer breakthrough time and better cut/puncture resistance, at the cost of dexterity.
Double-Gloving
Double-gloving — wearing a thinner, often different-material glove underneath a primary glove — is a standard mitigation for two distinct situations: working with a chemical known to have a short breakthrough time against the available primary glove material, and tasks with elevated puncture/tear risk where an inner glove provides a backup barrier if the outer glove is compromised. It is not a substitute for selecting the correct primary material; a poorly matched outer glove doubled with another poorly matched glove still fails quickly against the target chemical.
Change-Out Schedules: Time-Based, Not Just Visual
Because permeation is invisible, “the glove still looks fine” is not evidence that it is still protective. For any chemical with a known, short breakthrough time relative to the task duration, gloves should be changed on a defined schedule tied to that breakthrough time — for example, well before the standardized breakthrough time elapses, with a documented safety margin, rather than waiting for visible signs of degradation that may never appear. Gloves should also always be changed immediately after any known contact with the chemical being handled, after any visible sign of degradation or damage regardless of schedule, and between different chemical tasks to avoid cross-contamination.
Common Glove-Selection Mistakes
- Treating “nitrile” as one product. A blue 4-mil disposable exam glove and a green 15-mil unsupported chemical glove are both nitrile but perform very differently — always check the specific product’s chart, not the material family in general.
- Assuming dilute-chemical resistance implies concentrated-chemical resistance. Concentration changes permeation behavior; a glove rated well against a 10% acid solution is not automatically safe against the concentrated acid.
- Ignoring the SDS glove recommendation. Section 8 of a chemical’s Safety Data Sheet often names a recommended glove material directly — check it before defaulting to whatever glove is closest at hand.
- Skipping pre-use inspection. A quick visual check and stretch test catches penetration risk (pinholes, tears, weak seams) that no chemical-resistance chart accounts for.
- Waiting for visible degradation before changing gloves. Permeation frequently happens with no visible sign at all — schedule-based changes for short-breakthrough-time chemicals are not optional caution, they are the actual control.
Frequently Asked Questions
What’s the difference between glove degradation and permeation?
Degradation is visible physical damage to the glove material — swelling, cracking, dissolving. Permeation is invisible: the chemical moves through the intact material at a molecular level, so the glove can look completely fine while no longer providing protection. Permeation is measured by breakthrough time under ASTM F739.
What does an ANSI/ISEA 105 chemical class rating mean?
It’s a 0–6 scale translating a glove’s measured breakthrough time against a specific chemical into a simple class: Class 0 means breakthrough in under 10 minutes, Class 6 means at least 480 minutes (8 hours). The rating is specific to one chemical at a time — the same glove can carry different classes for different chemicals.
Is a nitrile exam glove safe for handling solvents like acetone?
No. Standard disposable nitrile exam gloves are thin, general-purpose barrier gloves, and nitrile as a material has poor resistance to acetone and many other polar solvents specifically — it degrades quickly. Solvent work calls for a glove material and product actually rated for that solvent, checked against a current manufacturer chart.
How often should chemical-resistant gloves be changed?
On a schedule tied to the specific chemical’s breakthrough time for the glove in use, with a documented safety margin — not simply “when they look worn.” They should also be changed immediately after any known chemical contact, any visible damage, or before switching to a different chemical task.
Does double-gloving make any glove safe for any chemical?
No. Double-gloving adds a backup barrier and is useful for short-breakthrough-time chemicals or elevated puncture risk, but it does not substitute for selecting a primary glove material genuinely rated for the chemical being handled.
Where can I find the recommended glove for a specific chemical?
Check Section 8 of that chemical’s Safety Data Sheet, and cross-check against the current chemical-resistance chart published by the glove manufacturer for the specific product (not just the material name) at the concentration actually in use.
Related CASRAI Guides
- PPE Selection for Chemical Handling in the Lab: Gloves, Eyewear, and Lab Coats — the parent guide to hand, eye, and body protection selection generally.
- How to Read a Safety Data Sheet (SDS): The 16-Section GHS Guide — where to find manufacturer-recommended PPE, including gloves, for a specific chemical.
- Understanding GHS Labels: Pictograms, Signal Words, and Hazard Statements — reading the hazard information that drives glove selection in the first place.
- Corrosive Chemicals in the Lab: Hazards, Handling, and First Aid
- Particularly Hazardous Substances in the Lab
- How to Write and Maintain a Chemical Hygiene Plan (OSHA 29 CFR 1910.1450)
- Chemical Spill Kits: What to Stock and How to Respond to a Lab Spill
