In 2014, USEPA stated they are no longer supporting the use of TANKS 4.09d (TANKS) as there are compatibility issues with certain computer operating systems. Although the model will remain on the USEPA website, USEPA is recommending the use of AP-42, Section 7 equations to calculate emissions. Additionally, the Texas Commission on Environmental Quality (TCEQ) released a guidance document earlier this month, stating that TANKS does not calculate emissions correctly for the following scenarios:
- Tanks located in areas with high ambient temperature (high ozone season)
- Heated and hot product storage tanks
Pinal County Air Quality Control District (PCAQCD) and Pima County Department of Environmental Quality (PDEQ) have recently confirmed the same deficiencies with TANKS. Both agencies will continue to allow the use of TANKS for instances where emissions are calculated correctly. However, for cases where TANKS would calculate emissions incorrectly, PCAQCD and PDEQ are now requiring emissions to be calculated via AP-42, Section 7 equations in conjunction with spreadsheet or software programs. Note that submittals should also include all intermediate calculation steps, sample calculations, and (for PCAQCD) references to how the method is consistent with TCEQ guidance.