@Melanie King, I just saw your post. I had a similar problem ad the sell fell through. But this is what I learned. The test are not accurate because the oil can be leaking through the belly where they cannot take samples. Also, if the tank is big (I forgot how many gallons) is better when removing. The companies that I contacted for removal told me that the bigger the tank the easier it was to remove because the frame will be able to stand the pressure when removing. But if the tank was small it would the risk of breaking when removing was much greater. Just ask those questions, if you haven’t, to the companies planning on removing the tank. I was also told that to clean an oil spill could be very expensive (over 100k sometimes, specially it there’s ground water) so be careful. Last, if the tank is working and this is for a rental you don’t have to remove it right away. Please post the outcome if possible; I am very interested in finding out how it went. Have a great day and good luck.