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What are Class 8 Corrosive Materials

May 2, 2020

Although no kind of hazardous waste evokes warm and fuzzy feelings, you have to admit that Class 8 is…well, a class unto itself. Consider: they’re liquids or solids that cause full-thickness destruction of human skin at the site of contact within a specified period of time.

As you might guess, anything capable of “the full-thickness destruction of human skin at the site of contact” will hold a special place in the bureaucratic bosoms of both the EPA and the federal DOT. State and local authorities are hardly disinterested parties, either.

Acids vs. bases

Class 8 corrosives are acids and bases. They differ by way of their pH levels, where “pH” stands for “potential hydrogen.” Or maybe “power hydrogen’.” Unless it’s pondus hydrogenii, which—when you pop into Google Translate and press the “Latin” button—comes up “weight hydrogen.”

There seems to be some controversy about it—at least among acid/base aficionados.

Anyway, the biggest difference between acids and bases is that acids give up hydrogen protons while bases receive them. And the movement of hydrogen in such a manner—in one direction or the other—is highly corrosive. Like, it burns.

The reference point is pure water, which has a pH = 7, meaning that hydrogen protons are more or less staying put and not causing any mischief. A substance with a pH level of less than 7 is an acid. Higher, and then it’s a base.

Obviously, the more acidic or alkaline a substance, the more corrosive it will be. But less obviously, the numbers aren’t linear. E.g., pH = 4 is ten times more acidic than pH = 5, and 100 times more acidic than pH = 6.  Similarly, pH = 13 is ten times more alkaline than pH = 12, and 100 times more alkaline than pH = 11. All of which is exponentially important to understand.

It’s not all about pH

Next time you crack open a Pepsi®, you might ponder that most commercial lemonades and sodas have a pH of about 2.5, not too far (thinking linearly for a moment) from hydrochloric acid (pH = 1.1 @ .380 concentration), which is definitely contraindicated as a soft drink.

To understand why you enjoy drinking one and would definitely not the other, bear in mind that in addition to pH, acids also sport something called “oxidizing potential.” This is their relative ability to strip electrons. The ingredients in soft drinks—while very acidic—nonetheless have little oxidizing potential. So drink up, and worry about it later.

Examples of Class 8 Corrosives

There are lots of them. Herein we list three common acids and three common bases, each in typical consumer/industrial concentrations:


  • Hydrochloric acid (HCL) (pH = 1.1 @ .380 concentration) is used in water and salt purification, as well as making batteries, fireworks, leather, and building materials. Your digestive system also produces HCL—but let’s not go there.
  • Sulfuric acid (H2SO4) (pH = 0.5 @ .335 concentration) is used to produce dyes, paints, pigments, explosives, and most ubiquitously: fertilizers and lead-acid batteries. This stuff is truly evil, uncontrollably boiling and bubbling when it accidentally comes into contact with plain old water.
  • Nitric acid (HNO3) (pH = 1.2 @ .680 concentration) has many of the same uses as H2SO4. It’s also used to remove warts, although we urge close adult supervision when doing so since it can also dissolve most metals. And mixed with HCL, it forms a fuming liquid used to dissolve gold and platinum—should such an exigency arise.


  • Ammonium hydroxide (NH4OH) (pH = 10.52 @ 1mM concentration) is used as a refrigerant, as well as for manufacturing detergents, textiles, soaps, ceramics, pharmaceuticals, inks, and explosives.  It’s also used to clean glass—and added to food to control acidity.
  • Potassium hydroxide (KOH) (pH = 10.98 @ 1mM concentration) shows up in the production of fertilizers, biodiesels, and soft soaps. It is also used as an electrolyte (in electrochemistry, of course), and in a process commonly called “chemical cremation” (which is exactly what it sounds like.)
  • Sodium hypochlorite (NaClO) (pH = 11 @ .05 concentration) is used in waste management, food production, and as a bleach or disinfectant. It’s also a pesticide.

Storage of Class 8 corrosives

Violent reactions between incompatible acids and bases can cause fires and explosions, as well as produce toxic and/or corrosive gases.

Storing Class 8 corrosives requires specialized cabinetry that—depending on your location—might require such features as self-closing doors that are close-fit, cannot swing inward, are “escapable” from the inside, and secured by at least two catches.

Other requirements might be the cabinet’s construction of corrosive-resistant material, or at least be protected by a corrosion-resistant lining or coating. Shelves should be perforated to accommodate airflow.

The cabinet’s base should form a liquid-tight sump—and probably be large enough to hold a specified percentage of its total capacity, should the worst happen.

Obviously, you should get expert advice, as that second-hand IKEA wardrobe you picked up at the neighborhood garage sale isn’t going to cut muster.

Oh…and blue. By convention—although not by law—cabinets designed for Class-8 corrosives are blue. And you do want to be in chromatic style, don’t you? Especially in the State of California?

Transportation of Class 8 corrosives

You just can’t throw this stuff in the back of your F-150 and haul it down to the dump. The dump won’t take it. And your F-150 is going to dissolve, whether you have the old steel job or the new aluminum one.

Instead, you need to finetune how you classify the material by assigning it into one of three (actually four) packing groups that are stratified according to the relative severity of the hazard it poses. These are:

  • Packing Group I causes full thickness destruction of intact skin tissue within 60 minutes of 3-minute exposure or less.
  • Packing Group II causes full thickness destruction of intact skin tissue within 14 days after 3-to 60 minutes exposure.
  • Packing Group III  # 1 causes full thickness destruction of intact skin tissue within 14 days after 1-t0-4 hours exposure.
  • Packing Group III  # 2 doesn’t cause full thickness destruction of intact skin tissue but corrodes steel or aluminum faster than 0.25 inch yearly (at a test temperature of 130°F).

What? You don’t know which substance burns skin faster than the other? Might we suggest you get expert advice? But onward…

Other shipping requirements include:

  • Shipping manifest. This is an EPA-required form-filling exercise completed by you. It indelibly attaches a hazardous waste to your enterprise as it migrates from your site to the hazardous waste management facility that will ultimately process it—along with all the legal, financial, and social liabilities that are endemic to hazardous material removal.
  • Labeling. Labels are always diamond-shape; and their size must adhere to international standards, measuring at least 4″ x 4″ (100 mm) on each side, square-on-point. The Class 8 variety graphically features liquids spilling from two glass vessels, respectively doing damage to a hunk of metal, and someone’s hand.
  • State-specific requirements. E.g., California (surprise!) has its own special requirements that include but aren’t limited to (1) the composition and physical state of the waste, (2) statement calling attention to its hazardous properties, (3) the generator’s name and address.

The upshot

Although it’s important to label, store, transport, and dispose of all nine categories of hazardous waste correctly, we nonetheless counsel our clients that Class 8 substances really deserve extra attention to detail—as might anything harboring the ghoulish potential to cause “full-thickness destruction of human skin.”

Don’t take chances. Secure properly licensed and experienced hazardous waste management experts to ensure that all consumer and commercial corrosives are properly stored, segregated, transported, and ultimately disposed of compliant with federal, state, and local standards.

The legal, financial, and reputational liabilities of not doing so are formidable.

Contact us today. (888) 681-8923

And thank-you for reading our blog!

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