The characteristic of corrosivity is one step of the hazardous waste determination process that you must complete for every waste stream that you generate.

Your waste is a corrosive hazardous waste, with waste code D002, if a representative sample has either of two properties:

1. It is aqueous and has a pH less than or equal to 2 or greater than or equal to 12.5, or
2. It is a liquid and corrodes steel of a specified grade at a specified rate.

For the first property determination aqueous means, “Of or containing water, typically as a solvent or medium”.  The regulation doesn’t specify how much water must be present in the sample, however the only approved test method (Method 9040C) requires the sample to contain at least 20% water.   If your waste does not meet this requirement, then you cannot use this method for determination of corrosivity and must proceed to the second property determination.

The second property determination is one much less known by the regulated industry.  It must be used to determine corrosivity in two circumstances:

1. The waste contains <20% water and therefore is not suitable for the first determination.
2. The waste passes the first determination with a pH of >2 or < 12.5.

40 CFR 261.22(a)(2) specifies Method 1110A for determining if a liquid sample is able to corrode  steel (SAE 1020) at a rate greater than 6.35 mm (0.250 inch) per year at a test temperature of 55 °C (130 °F).  The key word here is:  liquid.  If you don’t have a liquid waste, then you may not use this test method to determine corrosivity.

If it is not clear from the above, the US EPA does not recognize a solid material as having the characteristic of corrosivity; a D002 waste code may not be applied to a solid.  This may differ for your state however as some have included solids in the characteristic of corrosivity or have revised the test methods to encompass solids.

The US EPA description of the characteristic of corrosivity  is explained at 40 CFR 261.22.  A careful reading of this regulation is necessary to ensure your hazardous waste determination is accurate and complete.  Good training will help illuminate other areas of the regulations and how they impact your operations.