Counting dangerous waste

Counting calculator icon
You are required to determine whether the waste your business generates is dangerous waste, a process called designation. You also need to know how much waste you generate — we call that “counting.”

Counting is measuring the weight of your dangerous waste, including wastes that you:

  • Generate
  • Accumulate
  • Dispose
  • Treat
  • Recycle
  • Ship off site on a manifest

You may have to count some wastes you haven't thought of — for example, still bottoms. Meanwhile, there are wastes that do not get counted.

Why should I count my dangerous waste?

You are required to know how much dangerous waste you generate each month. The type and amount of waste you generate per month determines your "generator category." Your generator category determines which rules apply to your business.

Count your dangerous waste each month. The highest amount you generate (or accumulate) in any month is what sets your generator category. You may not average multiple months over time.

Counting waste is also important for your Dangerous Waste Annual Report and Pollution Prevention Plan.

Know the weight of your waste

You can weigh your waste with a scale or calculate the weight from a known quantity and density. Three ways to get the weight of your waste:

A) Weigh it

Weigh a smaller amount and multiply. For example, weigh one gallon of your waste, then multiply that weight by the total number of gallons you have. You can also weigh your waste containers before and after adding waste. The difference will be the weight of your waste.

B) Calculate with density

Knowing the density, or how many pounds are in one gallon of your liquid waste, can also help you calculate the weight. For example, a gallon of water weighs 8.34 pounds.

Start by estimating, then calculate if you are close to the limit. A 55-gallon drum full of water weighs about 458 pounds. If your 55-gallon drum is almost half full of liquid waste that has a density similar to water, you probably have 220 pounds or more of that waste. Some wastes have a significantly different density than water, so pay careful attention to what you have. A waste sludge may weigh much more.

C) Calculate with specific gravity

If you know the specific gravity of your waste, you can calculate the weight. The specific gravity is often listed on Safety Data Sheets (SDS or MSDS) for products that become waste.

  1. Multiply the specific gravity of the waste by 8.34 to get the density of your waste in pounds per gallon.
  2. Multiple that density by the number of gallons you have.

What not to count