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A disinfectant is not one thing. The chemical classes that healthcare guidance describes differ in which organisms they reach, what they damage and what they must never be mixed with. This guide sets those classes side by side using the CDC’s chemical disinfectant guidance, then shows how to read a product label against the EPA’s registration system, because the label, not the class name, is what you are required to follow.
Overview: what the class name does and does not tell you
The CDC’s healthcare guidance describes alcohols, chlorine compounds, quaternary ammonium compounds (“quats”), hydrogen peroxide, peracetic acid, glutaraldehyde, ortho-phthalaldehyde (OPA), iodophors and phenolics. Rather than rank the classes by a single activity level, the table below shows for each class whether spores are covered and what the known limits are.
Two rules from the CDC recommendations frame everything below. Critical items that enter sterile tissue or the vascular system are sterilized; semicritical items get at least high-level disinfection; noncritical surfaces such as bedrails and over-the-bed tables get low-level disinfection. And high-level disinfectants and liquid chemical sterilants are not to be used on noncritical surfaces. For the item categories, see high-level disinfection and the Spaulding classification.
Types table: classes, spore activity and stated limits
| Class | What it is | Spores | Limits (CDC) |
|---|---|---|---|
| Alcohol | Ethyl or isopropyl alcohol in water; optimum bactericidal range 60-90% by volume | Not sporicidal | Not recommended for sterilizing medical and surgical materials; flammable; evaporates quickly; can harden rubber and plastic and damage lensed instruments |
| Chlorine (sodium hypochlorite) | Bleach-type products; a 1:10 to 1:100 dilution of 5.25-6.15% sodium hypochlorite is cited for blood spills | Described by the CDC as sporicidal | Corrosive to metals above 500 ppm; inactivated by organic matter; releases toxic gas if mixed with ammonia or acid |
| Quaternary ammonium | Includes benzalkonium chloride; good cleaning agents | Not sporicidal; generally not tuberculocidal | Intended for ordinary sanitation of noncritical surfaces; hard water reduces effect; cotton and gauze absorb the active ingredient; occupational asthma reported with benzalkonium chloride |
| Hydrogen peroxide | 3% is described as stable and effective on inanimate surfaces; a 7.5% product with 0.85% phosphoric acid is a sterilant | No spore claim for 3%; the 7.5% product is a sterilant | Can discolor black anodized metal |
| Peracetic acid | Sporicidal; also used in a 0.23% peracetic acid with 7.35% hydrogen peroxide sterilant | Sporicidal | Unstable, especially diluted; corrodes copper, brass, bronze, plain steel and galvanized iron; one endoscope maker found the combination product incompatible with its flexible GI endoscopes |
| Glutaraldehyde | 2% or stronger aqueous, buffered to pH 7.5-8.5; high-level disinfectant and chemical sterilant | Sporicidal when activated to alkaline pH; a chemical sterilant | Too toxic and expensive for noncritical surfaces; vapor can cause irritation and asthma |
| Ortho-phthalaldehyde (OPA) | 0.55%; no activation needed, stable from pH 3 to 9 | Not sporicidal in 270 minutes at 0.5% | Contact time of 12 minutes in the United States; stains proteins gray, including unprotected skin |
| Iodophors | Bactericidal, mycobactericidal and virucidal | Not sporicidal | Not for use on silicone catheters |
| Phenolics | Bactericidal, fungicidal, virucidal and tuberculocidal at use dilution | Not sporicidal | Not FDA-cleared as high-level disinfectants for semicritical items; absorbed by porous materials; caution in nurseries because of hyperbilirubinemia in infants in bassinets |
Source for the whole table: CDC, Chemical Disinfectants (checked 2026-10-29). The “does alcohol sterilize” question is answered by the first row: no, it is not sporicidal.
How to choose by setting
The CDC guidance organizes the decision by what the item is and what contacts it, not by building type, so the same logic applies in every setting. Where a setting differs is mostly in which items it handles.
- Home care: items are noncritical surfaces and equipment, for example a blood pressure cuff or a bedrail. The CDC recommends an EPA-registered hospital disinfectant for noncritical devices, applied according to its label.
- Clinic: adds semicritical reusable items, which need at least high-level disinfection, and any critical instruments, which are sterilized. The reprocessing method for a device follows that device’s manufacturer instructions; a chemical class that is compatible with one instrument may not be with another.
- Hospital: the same three item categories apply at larger scale. Cleaning with water and detergent, or with water and enzymatic cleaners, comes first; see enzymatic cleaners. For room cleaning, see terminal cleaning.
- Laboratory: bench surfaces and equipment are noncritical surfaces in the CDC’s terms. Choose a product whose label lists the organism you need covered and check the class limits above, such as chlorine corrosion of metals or the flammability of alcohol.
High-level disinfectants and sterilants such as glutaraldehyde belong to device reprocessing and are not used to wipe down noncritical surfaces. Alcohol is covered in more depth in what isopropyl alcohol is; the difference between a disinfectant and a sanitizer is in disinfectant vs sanitizer.
What to check on the label
The CDC states that, by law, all applicable label instructions on EPA-registered products must be followed. The EPA’s page on selected registered disinfectants says the product should be used according to its Use Directions. Four things on the label matter most.
- EPA registration number. It identifies the product. A two-part number such as 1234-12 is the primary registration; a three-part number adds a distributor number.
- The claim you need. The EPA publishes lists by target, including List A (sterilizers), B (tuberculosis), G (norovirus), H (MRSA and VRE), K (Clostridioides difficile spores), N (SARS-CoV-2), P (Candida auris) and S (bloodborne pathogens such as HIV, HBV and HCV). A product on the list for your target has a label claim for it; the class name alone does not.
- Contact time. This is how long the surface must stay visibly wet. If it dries sooner, the EPA says to reapply. Follow the contact time printed on the product label.
- Use dilution. Dilute exactly as directed; the CDC repeats “dilute per label” for phenolics, and gives dilution ranges for chlorine only as examples.
For the full label-reading and material-compatibility workflow, see surface disinfectant selection, contact time and material compatibility.
Care and replacement
Storage, dilution life and expiry vary by product, so follow the label and the manufacturer’s instructions for use. Two class-level points from the CDC are worth knowing: peracetic acid is unstable, particularly once diluted, and chlorine is inactivated by organic matter, so clean visible soil before applying it. Never mix chlorine products with ammonia or acids; the CDC warns of toxic gas.
FAQ
Does alcohol sterilize?
No. The CDC describes alcohol as not sporicidal and not recommended for sterilizing medical and surgical materials.
Can bleach be mixed with other cleaners?
Not with ammonia or acids. The CDC states that chlorine mixed with either produces toxic gas.
Is a quat the same as a high-level disinfectant?
No. The CDC places quats in ordinary environmental sanitation of noncritical surfaces, and they are not sporicidal.
Is a disinfectant the same as a sanitizer?
No. See disinfectant vs sanitizer.
Sources
- CDC, Chemical Disinfectants, checked 2026-10-29.
- CDC, Summary of Recommendations, Disinfection and Sterilization, checked 2026-10-29.
- US EPA, Selected EPA-Registered Disinfectants (page updated 2026-08-24), checked 2026-10-29.
