Since this is a blog, it doesn't even have the benefit of built-in (although perhaps suspect these days) credibility of investigative journalists and editorial vetting at the NYT, Guardian, WSJ, etc. One would imagine that such outlets would have reporters on flights immediately. A spill larger than the Valdez would certainly be news-worthy!
There are no photos of this spill in the article, except for a photo of some tainted water that could be anywhere and an irrelevant photo of salt-water contamination. I'd think that a spill of this magnitude would have highly visible proof from drone or even satellite photos, on the ground, etc. Did all of the gas condensate, and evidence, seep into a massive hole in the ground?
The sole piece of "evidence" is what appears to be an email with all identifying information, logos, etc removed. Even the alleged company or investigating agencies are redacted. It doesn't appear to be an official form, purchase order, etc. It could have been completely fabricated in ten minutes in Google Docs. No deep fakes necessary.
In fact, @mods, the HN headline should probably be changed from the submitter's Whistle-blower reveals N Dakota leak of 11M gallons of gas condensate in 2015 to the actual Did North Dakota Regulators Hide an Oil and Gas Industry Spill Larger Than Exxon Valdez? Even the blog's headline is a question and not an answer.
As hackers/scientists/intellectuals, we should be asking for facts, hard data, and photographic evidence.