This was apparently a Linde installation custom built for TSMC in Arizona.[1] Nitrogen, oxygen, and argon are extracted from air on-site and purified. That's Linde's primary business; liquefying and distilling air. This isn't some little local company or a company operating outside their area of expertise.

Those gases are storeable, so it's surprising there wasn't enough tank capacity to deal with outages.

The site plan [2] shows "Gas Plant 1", and future "Gas Plant 2" and "Gas Plant 3". The gas plants are across a small road from the fab and feed the plant directly. Once Gas Plants 2 and 3 were built, there would be redundancy, but at this stage, there isn't a backup. The plan doesn't show a large tank farm, so they can't store gases in bulk.

[1] https://www.aztechcouncil.org/utility-company-makes-progress...

[2] https://semiwiki.com/forum/threads/tsmc-phoenix-arizona-fab-...