In accordance to their increasing size and strength, the Defense Corps created a "Category" scale, classifying Kaiju on the basis of toxicity and water displacement.

Referred from http://pacificrim.wikia.com/wiki/Kaiju

Definition of toxicity is "The degree to which a substance (a toxin or poison) can harm humans or animals."

So my question is did Kaiju release toxins? If so, what impact did these have on organisms around?

3 Answers 3


According to the Pacific Rim wiki:

Upon decomposing, their bodies release a noxious agent into the air known as "Kaiju Blue", their blood. Kaiju Blue has the ability to contaminate the air and its immediate environment, making it uninhabitable. The blood of a Kaiju is highly acidic, corroding anything in its path. This makes it especially hard to gather samples safely for examination and experimentation. As a result, Jaegers have been equipped with weapons that cauterize wounds they inflict on Kaiju to prevent the spread of their highly acidic internal fluids[11]. As silicon-based organisms, the design of their bodies makes it difficult to determine and study particular parts of their internal systems

So the Kaiju themselves are not toxic, but their blood is very much so as it contaminates the area immediately around them when they die.

  • So the toxicity comes from the blood. Almost a perfect weapon.
    – Vishvesh
    Commented Apr 10, 2015 at 11:00
  • @Vishvesh Apparently so yes.
    – Daft
    Commented Apr 10, 2015 at 11:00
  • @Vishvesh Not so much: you have to be dead for your weapon to be effective Commented Apr 10, 2015 at 13:02
  • 2
    @Maël Nison Not a weapon for the kaiju themselves, but for the ones who sent them.
    – Whelt
    Commented Apr 10, 2015 at 13:56

The blood of the Kaiju is ammonia-based. Per Guillermo Del Toro:

"The second thing that the Kaiju do which is, they decompose and they release an agent called Kaiju-[blue] that completely destroys the cities, makes the air impossible to breathe. The blood is completely acidic. So they figure out that the base of fluid of the Kaiju is ammonia-based. So how do they neutralize it? But it takes a while because, first of all, it melts the pavement, melts the structures around it, makes a noxious gas. By the time they get to a Kaiju, the first few attacks, they can't even get samples or corpses or pieces to analyze it. The Kaijus are essentially triggered to self destroy if they fall. So it's a very smart weapon."

As seen in this video from Comicon prior to the 2013 release of the movie -

Ammonia is quite toxic to marine life, per this from Wikipedia:

The toxicity of ammonia solutions does not usually cause problems for humans and other mammals, as a specific mechanism exists to prevent its build-up in the bloodstream. Ammonia is converted to carbamoyl phosphate by the enzyme carbamoyl phosphate synthetase, and then enters the urea cycle to be either incorporated into amino acids or excreted in the urine. Fish and amphibians lack this mechanism, as they can usually eliminate ammonia from their bodies by direct excretion. Ammonia even at dilute concentrations is highly toxic to aquatic animals, and for this reason it is classified as dangerous for the environment.

Even though it is not usually toxic to humans and mammals, we can get what is called Hyperammonemia, which is an excess of ammonia in the blood system. It is a dangerous condition that may lead to encephalopathy and death.

It seems anyone caught up in the Kaiju-Blue aftermath would have adverse side effects. As Guillermo Del Toro stated, they are a very smart weapon.

  • @phantom42 - Thanks. I was wondering why it wasn't popping. Commented Apr 10, 2015 at 13:07
  • "Ammonia" "highly acidic" sigh.
    – Broklynite
    Commented Apr 18, 2017 at 8:38
  • @Broklynite - glad it's their words and not mine. Although, by "acidic" I think they are suggesting the action created of dissolving things, not necessarily where it lies on the ph scale. Commented Apr 18, 2017 at 10:01
  • I disagree, I think you may be thinking of "caustic" or possibly "corrosive". Then again, I'm a pedantic chemist.
    – Broklynite
    Commented Apr 18, 2017 at 13:50

Directly from the intro of the movie:

(newscaster on tv): The acid factor of the Kaiju blood creates a toxic phenomenon named Kaiju Blue.

From the official novelization:

“Plus nobody can get Kaiju Blue if it’s at the bottom of the ocean, right?” Raleigh added. Kaiju Blue was bad news, a kind of shock reaction the human body suffered when recently dead kaiju started to off-gas toxins in the hours after they died. It killed a lot of people when kaiju went down in populated areas . Today it would only kill fish, and who knew if they got Kaiju Blue, anyway?

The blood is also corrosive:

The dying kaiju’s blood , bright blue and as corrosive as any substance found in nature, smoked and sizzled its way across the asphalt and concrete.

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