Questions and Answers
Start at Tier A and determine if there is enough good quality data to evaluate it. If so, determine if the data accounts for all hazardous substances in the source. If they do, stop there. If they do not, continue through the other tiers until one is " adequately determined" or Tier C or D are evaluated.
The most hazardous substance at a site does not have to exist in every source.
If the site hazardous waste quantity is close to a breakpoint, determine if a small change will make any difference in the site score. If so, be especially careful of the data quality and documentation and determine if the minimum values apply.