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Comment by xyzzy21 | Hacker News Reader

Ammonia is like hydrogen - not a fuel source but merely a fuel storage medium.

Further we used to common use ammonia for refrigeration before Freon became a thing - the reason we don't use it for that except in very limited large scale applications, is that it's SUPER POISONOUS and prone to leaking and killing.

So pushing ammonia is another example of solving one problem but creating 5-10 more problems which our society ALREADY KNOWS WILL HAPPEN - because we've been there before and abandoned it for safety, economic and environmental reasons. It's willful ignorance of history and science.

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Ammonia is not super poisonous, just kind of poisonous. We routinely handle it in industrial amounts, and an ammonia leak is much less harmful than something like a hydrazine leak.

Industrial production and consumption of ammonia is the basis of the fertilizer industry. There's not many hazardous chemicals we have more experience in handling safely in bulk than this stuff.

Of the 57,975 incidents that were reported, 54,989 (95%) involved the release of only one chemical. The top five chemicals associated with injury were carbon monoxide (2,364), ammonia (1,153), chlorine (763), hydrochloric acid (326), and sulfuric acid (318). Carbon monoxide and ammonia by far caused the most injuries, deaths, and evacuations. Chlorine, while not in the top 10 chemicals released, was in the top five chemicals associated with injury because of its hazardous properties....

In ammonia incidents, the industry with the highest frequency of injured persons was manufacturing of food, textile, and apparel (451 [39%] of 1,153 injured persons). The subsector food manufacturing had the highest number of injured persons and agriculture, forestry, fishing, and hunting had the second highest frequency of persons injured from ammonia releases.

-- "Top Five Chemicals Resulting in Injuries from Acute Chemical Incidents — Hazardous Substances Emergency Events Surveillance, Nine States, 1999–2008", Ayana R. Anderson, MPH, Division of Toxicology and Human Health Sciences, Agency for Toxic Substances and Disease Registry, CDC

https://www.cdc.gov/mmwr/preview/mmwrhtml/ss6402a6.htm

Agricultural use of ammonia is strongly characterised by use in unconfined and well-ventilated spaces. Relatively few people are involved with its use, and those who are tend to be reasonably familiar with risks and precautions. It remains one of the top five most dangerous chemicals.

Notably absent from that list are hydrocarbon fuels, despite their considerably wider use by an almost completely untrained cohort.

Widespread use as a fuel would likely increase risk and exposure to ammonia, as well as its use within confined spaces in which the likelihood and impacts of accidental exposure would be greatly increased.

Notably absent from that list are hydrocarbon fuels,

Sure, but carbon monoxide is a product of burning fossil fuels, so the fossil fuel cycle has it's poison dangers.

Most combustion will produce some noxious byproducts, and absent the very expensive catalyst mentioned in TFA, ammonia also releases high levels of NOx (nitrous oxides).

CO has a lower possibly lethal concentration of about 200 ppm (with long exposure), though higher levels will cause more rapid and severe issues, with levels from 800 to 12,800 resulting in death in from 2--3 hours to a few minutes. Auto exhaust concentrations without a catalytic converter are 35,000 ppm.

https://www.abe.iastate.edu/extension-and-outreach/carbon-mo...

In the case of ammonia, it is the fuel itself which is toxic.

LC50 (lethal concentration, 50% mortality) varies by duration of exposure, from 40,300 ppm (10 min) to 2,000 ppm (4 hr). LC50 for 30 minutes exposure ranges from 200--2,000 ppm.

https://www.cdc.gov/niosh/idlh/7664417.html

Note that the kill mechanisms differ markedly. CO binds to hemoglobin, preventing oxygen from doing so, and effectively asphyxiating the victim. Treatment with oxygen should promote recovery in most cases. Ammonia is chemically caustic, exothermic when hydrating, and chemically induces necrosis and tissue death, most notably in the lungs if inhaled. Treatment and recovery are far more critical than with CO.

https://www.ncbi.nlm.nih.gov/books/NBK546677/?report=classic

On top of that, CO is a fractional exhaust product whilst ammonia is the hyperabundant fuel. Any fuel spill or partial combustion presents and immediate and severe inhalation threat.

It's best to avoid both. Ammonia strikes me as the markedly greater risk.

With exposure to organic combustion virtually universal, CO poisoning deaths in the US range about 438/yr (1999--2012), or 1.48/million. From the accompanying map of case intensity, I'd surmise indoor heating is a principle risk case, with cases concentrated in northern and Rocky Mountain states. On balance, that's a fairly low per-person risk, the overall incidence rate is a measure of net exposure.

https://pubmed.ncbi.nlm.nih.gov/26032660/

In my earlier comment, CO has nearly exactly twice the incidents as ammonia, though I strongly suspect that this is based on a vastly larger potentially-expose population. Even with very limited exposure to potential poisoning, ammonia represents an absolute risk half that of CO, which has universal exposure.

If ammonia is safe enough for agricultural use, then it may also be sensible for other large-scale applications, like powering ships and industrial processes.

You definitely wouldn't want it in your car though.

If by safe you mean one of the things farmers fear the most in an already dangerous job. Even as a kid working around farm equipment, silos, and all sorts of dangerous chems, I was warned to stay far away from any ammonia tanks, and farmers are never having a good time when they are hauling a tank of it. Tank full of pesticide? "Yeah go ahead and put some in a pop bottle and mix it with random shit you find in the barn and throw bugs in it" An ammonia tank? "Don't even go near it, especially if it is being used or being hauled."

Well, gasoline isn't exactly a benign substance, either.

It would be interesting to compare the number of people burned to death in gasoline fires to those poisoned by ammonia vapor.

My gut tells me that gasoline is currently responsible for more fatalities, but I don't have any hard facts on that.

Of course the number of ammonia deaths would go up to some degree if it were used in cars, but that would be offset by fewer gasoline deaths.

If we're gonna have an energy economy based on nitrogen fuels, I'd vote for the even spiffier hydrazine. What could possibly go wrong?

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