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Comment by e44858 | Hacker News Reader

Ammonia fuel pumps will not be a fun place to hang out: "Anhydrous ammonia is stored as a liquid under pressure. When released to the environment, though, it becomes a toxic gas. Liquid anhydrous ammonia expands 850 times when released to ambient air and can form large vapor clouds. It may aerosolize and behave as a dense gas, even though it is normally lighter than air. Anhydrous ammonia may also cause water vapor to condense in the air forming a visible white cloud. Therefore, when anhydrous ammonia is released to the air, it may travel along the ground in a cloud instead of immediately rising into the air and dispensing." https://msdh.ms.gov/msdhsite/index.cfm/43,320,230,349,html

Imagine a gas station that's perpetually covered in a blanket of toxic fog that drifts to nearby homes and fills in their basements.

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Exactly. It's enough to have to use it in very much diluted form to clean surfaces prior to painting to give you a very healthy respect for the kind of accident that can result from having a concentrated amount in an enclosed space or a newly formed cloud of gas resulting from a leak.

Here is the MSDS on Ammonia:

https://www.airgas.com/msds/001003.pdf

On the flip side the smell and eye watering and lung burning is so strong that even the smallest leak cannot go undetected for a second. There can never be any such cloud except in the case of an accident. At all other times the tiniest leak anywhere will make everyone scramble and shut valves off.

Ammonia will cause serious lung damage if concentrated. Small leaks won't go undetected, large ones will be catastrophes. Think: parking garage leak.

0.5% and you're looking at respiratory arrest and 1% and up and you will have skin damage (think burn wound but chemically induced rather than fire).

That won't be a real problem because you're likely going to be dead anyway...

I do believe this. I don't know what their plans are for making the mass almost uncontrollable distribution and handling infrastructure safe, but I can't believe it can ever be as safe as gas or diesel. I mean you can carry enough energy to move tons of weight for dozens of miles at high speed and up hills, in a plain open pail like water, or a milk jug, and drop it, spill it all over yourself, throw a lit cigarette right into it... And it doesn't explode or anything.

I can imagine ways to make the car tank reasonably safe in car crashes, just by making the tank good and strong and protecting it along with the passengers such that anything bad enough to hurt the tank already killed everyone anyway, and anything short of that, there could be a pretty simple mechanical auto shutoff inside the tank that seals up all the pipes from the inside and the only thing to escape will be the contents of the lines, and the lines can be thin. So I'm actually not that worried about car crashes.

But the number of infrastructure bits that all need to be mechanically sound and properly maintained and not old, bent, chewed up or worn seals, corroded, abraded, rusted, dirty with sand, ice, hit with a back hoe, ruptured from ice or tree roots, etc etc...

If it's a calm humid day, the ammonia will combine with moisture to form a vapor that's heavier than air, so it will settle to the ground instead of dissipating. That means if you have even a tiny leak from the pump nozzle, over time it would accumulate in low-lying areas like basements.

Wow, 850% expansion might give Toyotas an upper edge in collisions if the fuel tank is compromised.

It's not percent

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