Frequent Questions

We have questions regarding allowable adjustments to EPA Method 555 (like adding in a rinse step). Are adjustments, in general, allowable?

EPA Method 555 is an old method that has been supplanted with far better methods, especially EPA Method 515.4. But – if a lab wants to use it, they are stuck with the method ‘as written.’ Old methods were written in a prescriptive manner and labs are expected to follow them without deviation.

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