Just checking this makes sense

I suspect that there is a more appropriate word than 'uphold'. I suggest:

"The company has maintained this safety certification for many years."

Thanks. I like your suggestion.

If the company wanted to use the word "upheld", surely they would have to say something like "The accrediting body has upheld the company's safety certification for many years." My reason for thinking this is that the company isn't agreeing to the previous decision, the accrediting body is.

I think "maintained" is more fitting. "Upheld" gives me the impression that someone is disputing the accrediting body's decision to certify the company.