I removed this part of the introduction:

The timeline they predict can be found here.

If there ever was a timeline in that article, it's been deleted. It looks like there was even a motion to delete the article entirely, judging from what Wikipedia Updaters said on its discussion page:

"I suppose the History Channel stepped into the breach because we don't have an 'Unverifiable Speculation Posing as Science Channel'. Does any contributor wish to make the case why 'Life after People' is worthy of an extensive entry in Wikipedia? Do we have to accept that everything shown on TV, regardless of its worth, is inevitably notable because it is seen by a lot of people and will inevitably have an impact? [This paragraph by se16teddy]"

Just another reason why Wikipedia Is Unreliable, I suppose.

Below I removed, as I feel that it was getting stupid. Revert if you can prove otherwise.

• Fortunately, all of the nasty stuff will have decayed to background levels after only six, or seven hundred years. The long lived stuff is barely radioactive (there is an inverse relationship between half-life and radioactivity). If the Romans had nuclear power for a while and buried all of the evidence, the only telltales would be finds of depleted uranium— like at Oklo, careful chemical analysis would reveal the truth, but one of the signs is that it would be less radioactive than expected.
• Exactly. And this thing is stupid, non Restricted knowledge will simply not be lost in Modern times bar Apocalypse. Anything of the scale that will leave the future without knowledge of the Cold War and nuclear power will give the future more pressing problems to worry about than a few semi radioactive landfills.
• Not really. If society utterly collapsed today, took 6000 years to rebuild again (approximately first agricultural societies to modern), then repeat a few times, at the end of the third cycle some of it wouldn't be through a single half-life.
  • And the entire point mentioned above is that something has a half-life of 18,000 years, its radioactivity is so piss-weak you wouldn't even be able to find it without sensitive equipment and knowing what to look for.

• Totally incorrect, as the National Academy of Sciences says the time of peak risk might approach a period of one million years. See this page on The Other Wiki. Of particular concern are two long-lived fission products, Technetium-99 (half-life 220,000 years) and Iodine-129 (half-life 15.7 million years), which dominate spent nuclear fuel radioactivity after a few thousand years. The most troublesome transuranic elements in spent fuel are Neptunium-237 (half-life two million years) and Plutonium-239 (half-life 24,000 years).

That site is talking about the time of peak risk from long-lived isotopes which is not the same as the time of maximum danger, taking all the isotopes into account, so it doesn't contradict the paragraph, as it currently stands. Also, there are various complication in the definition and calculation of risk, as well as a lack of complete consensus about the underlying science, none of which it is really appropriate to go into here.

Rather than weighing down the example with excessive detail and debate, it's best to just sketch the general situation. If people want the full picture, they can go elsewhere.

I removed:

"** Fortunately, all of the nastiest stuff will have decayed to background levels after only six, or seven hundred years. The longest lived stuff is barely radioactive (there is an inverse relationship between half-life and radioactivity). If the Romans had nuclear power for a while and buried all of the evidence, the only telltales would be finds of depleted uranium — like at Oklo, careful chemical analysis would reveal the truth, but one of the signs is that it would be less radioactive than expected."

Since it isn't true.

Especially, "The longest lived stuff is barely radioactive (there is an inverse relationship between half-life and radioactivity)." Is total crap.

Plutonium, which arguably is the most deadly substance on Earth (the only argument is that I guess the poison Ricin or Botox might be considered more deadly if you managed to get some, but those pretty much have to be given to one person at a time, while Plutonium can just be scattered) has a half life of anywhere from 88 years to 80 million years, depending on the isotope.

The Plutonium part of spent civilian power reactor fuel typically has under 70% Pu-239 (half life of 24,100 years) and around 26% Pu-240 (half life of 6563 years), the rest being made up of other plutonium isotopes,