# Slaughtering pigs: CO2 suffocation from burning gasoline **URL:** \ **Category:** Factual Questions\ **Created:** [September 23, 2021, 5:52am UTC](https://boards.straightdope.com/t/slaughtering-pigs-co2-suffocation-from-burning-gasoline/951162 "2021-09-23T05:52:23Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [September 23, 2021, 5:52am UTC](https://boards.straightdope.com/t/slaughtering-pigs-co2-suffocation-from-burning-gasoline/951162/1 "2021-09-23T05:52:23Z")
There was a small article in today’s newspaper about how they’re having a problem in the UK regarding pigs. It seems pigs are slaughtered by suffocation with CO2, but the price of gas (er petrol) is too high, so they stopped doing so. It didn’t say so explicitly, so I assume they burn the fuel to generate the CO2. Now there’s tens of thousands of pigs waiting to be slaughtered. This makes me wonder: couldn’t they find some other way to get the CO2? Carbon dioxide is already produced by a number of other ways, so wouldn’t it be cheaper to capture it from someone’s smokestack? ---
**Author:** ![Martin\_Hyde](https://avatars.discourse-cdn.com/v4/letter/m/47e85d/32.png) [@Martin\_Hyde](https://boards.straightdope.com/u/Martin_Hyde)\ **Post date:** [September 23, 2021, 6:06am UTC](https://boards.straightdope.com/t/slaughtering-pigs-co2-suffocation-from-burning-gasoline/951162/2 "2021-09-23T06:06:14Z")
From what I can see CO2 used for meat production (specifically stunning pigs before slaughter) is provided by industrial gas supply companies, they get the CO2 primarily as a byproduct generated from ammonia plants. I don’t know if much or any of it is produced by burning gasoline, considering there are a number of processes at industrial scale that generate the gas as a byproduct I have to think those would be preferable to burning gasoline which is itself a somewhat variable priced and always high in demand commodity. ---
**Author:** ![UDS1](https://avatars.discourse-cdn.com/v4/letter/u/e47774/32.png) [@UDS1](https://boards.straightdope.com/u/UDS1)\ **Post date:** [September 23, 2021, 6:31am UTC](https://boards.straightdope.com/t/slaughtering-pigs-co2-suffocation-from-burning-gasoline/951162/3 "2021-09-23T06:31:52Z")
CO2 production in the UK is mainly a by-product of the manufacture of nitrogen-based fertilisers, which is an energy-intensive process. “Gas prices” in the UK have nothing to do with the price of petrol; the reference is to the price of natural gas, from which much of the UK’s electricity supply is generated. As gas prices have spiked in the UK fertiliser manufacture is currently very expensive, so producers have lowered production and are filling orders from stockpiles accumulated in happier times. They’ll rebuild the stocks back up when gas prices fall. They just don’t have similar CO2 stockpiles, so they can’t fill orders for CO2. Hence the problem. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [September 23, 2021, 6:38am UTC](https://boards.straightdope.com/t/slaughtering-pigs-co2-suffocation-from-burning-gasoline/951162/4 "2021-09-23T06:38:49Z")
Looks like I made an incorrect assumption about what gas was involved. Thanks for the correction Martin and UDS1. I tried to find more info on this with Google, but all I found was complaints that there was a shortage of butchers due to Brexit. ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [September 23, 2021, 11:08am UTC](https://boards.straightdope.com/t/slaughtering-pigs-co2-suffocation-from-burning-gasoline/951162/5 "2021-09-23T11:08:30Z")
> [@dtilque](#): > > so wouldn’t it be cheaper to capture it from someone’s smokestack? Your original question was answered, but your intuition was spot-on here. The reason they capture it from ammonia production is because that’s a process with a high concentration of CO2. Not the ammonia loop itself, but the production of hydrogen from methane and water. More in the wiki link below. Capturing from SMR is easier than from coal exhaust, which is easier than from natural gas exhaust (combustion for electricity generation, not hydrogen production.) > **[Steam reforming](https://en.m.wikipedia.org/wiki/Steam_reforming)** > > Steam reforming or steam methane reforming (SMR) is a method for producing syngas (hydrogen and carbon monoxide) by reaction of hydrocarbons with water. Commonly natural gas is the feedstock. The main purpose of this technology is hydrogen production. The reaction is represented by this equilibrium: > The reaction is strongly endothermic (ΔHSR = 206 kJ/mol). > Hydrogen produced by steam reforming is termed 'grey hydrogen' when the waste carbon monoxide is released to the atmosphere and 'blue hydrog... > **[Water–gas shift reaction](https://en.m.wikipedia.org/wiki/Water%E2%80%93gas_shift_reaction)** > > The water–gas shift reaction (WGSR) describes the reaction of carbon monoxide and water vapor to form carbon dioxide and hydrogen: > The water gas shift reaction was discovered by Italian physicist Felice Fontana in 1780. It was not until much later that the industrial value of this reaction was realized. Before the early 20th century, hydrogen was obtained by reacting steam under high pressure with iron to produce iron oxide and hydrogen. With the development of industrial processes that required...