Opposite of Redundant?

We all like having redundancy in our systems, where the failure of a single component does not cause catastrophic failure.

What word would you use to describe the opposite of redundant?  Where failure of any component of a multi-component system causes catastrophe?  I can't seem to think of a word in the English language to describe this concept.

Here is an example of what I'm talking about.  In this rappel setup, failure of either bolt means decking.  

UNdundant. 

So if you don't put the rope through the ring, that's a problem? Um, maybe a better example would help spur conversation. The setup in the photo is absurd.

Edit: Sam, are you aware of how to use the inline bolts in the photo for rappeling?

Dependent, but there's probably a better word.

Something about how the failure of "any link in a chain" causes disaster.

Your photo is quite a laugher! - shows how dumb some people really are.
Or it's a troll.
Almost as bad as toproping through slings with no biner.

unique

Part of a system without redundancies are considered to be a single point failure. 

Yergonnadieant.

FrankPS wrote: So if you don't put the rope through the ring, that's a problem? Um, maybe a better example would help spur conversation. The setup in the photo is absurd.

Edit: Sam, are you aware of how to use the inline bolts in the photo for rappeling?

For everyone else having trouble keeping up, I'll make things more clear.

1)Yes, this pictured setup IS absurd, that's my point.  This pic actually comes from the Un-Belay-vable series on climbing.com

2)In the pictured setup, if either bolt fails, you fall.  If instead the rope were threaded through through the ring, if either of the bolts fail you live (a redundant system)

3) Yes, Frank, I am aware how to use inline bolts for raps.

James Sevigny wrote: Part of a system without redundancies are considered to be a single point failure. 

This

...non-redundant.

Etymologically speaking redundant doesn’t have a prefix and therefore a word like “dundant” doesn’t exist. I think words like unique, essential or more superfluously “single point of failure” in this context are appropriate. 

Negligent.

Obviously Single Point Failure is best because it can be abbreviated SPF and then we can rank possible failure in terms of likelihood, say SPF10 SPF20 SPF30 etc.

Single point failure encompasses America. Don't be an SPF

Janky.

The mathematics term "irredundant" would work in the anchor context.

Swedish rigged (they have the highest suicide rate). 

Nathan Sullivan wrote: Janky.

I've changed my mind. I throw my support behind Janky.

Sam Skovgaard wrote: What word would you use to describe the opposite of redundant?  

dispensable : - ) 

Committing

Mountain project is often not helpful. You might get a legit response from stackexchange.com. I think they have a language section or something.

Actually:
https://english.stackexchange.com/questions/247993/what-is-a-good-antonym-for-redundant-engineering/248015#248015