Generally the limitation on back taxes is 10 years according to this source[1], but there is no limitation in the case of filing a fraudulent or false return or willfully attempting to evade tax. [2] is the official source. I dug around a bit and it looks like it is the same for businesses as individuals although I haven't got a source that says that crisply.

[1] https://www.findlaw.com/tax/tax-problems-audits/what-is-the-.... [2] https://www.irs.gov/filing/statutes-of-limitations-for-asses...