Carbon monoxide, CO, is a toxic, colorless, odorless, tasteless gas. Concentrations as low as 667 ppm may cause death. Symptoms of carbon monoxide poisoning include headache, nausea, vomiting, dizziness, fatigue, and a feeling of weakness.
It can be prepared by burning charcoal in a low oxygen environment. A 1 m oven exhaust tube on a grid, half filled with charcoal and lit will suck air into the bottom where the oxygen reacts with charcoal to form CO2. Further up in the tube there is little or no oxygen left and the CO2 will react with charcoal to form CO (all the charcoal must be hot for this to work). The empty upper part of the tube prevents the hot CO from mixing with air and burning to CO2. CO leaves the top end of the tube. This setup should work in a room with normal oxygen level, but may be mechanically unstable and easily knocked over, potentially causing burns or a fire.
A charcoal grill is made to be more stable, but is less effective in making CO. They have been successfully used for suicide, though.
The intense heat and fumes of burning charcoal can be a problem in a small space.
CO can be made by mixing and heating formic acid or oxalic acid or their salts, with concentrated sulfuric acid.
Old cars without a catalytic converter produced CO in their exhaust and were a common suicide method. In modern cars the catalytic converter turns CO to CO2 and makes it hard or impossible to commit suicide. However, the converter must be hot to work effectively, so when the car is started when the converter is cold and the engine is running idle there may be enough CO.
Side effects of CO poisoning may be severe.
Warning signs can help avoid other people to enter the toxic environment.
Oral ingestion of a small quantity of solid or dissolved cyanide (e.g. sodium or potassium cyanide, not cyano ferrate) as little as 200 mg, or to airborne cyanide of 270 ppm is sufficient to cause death within minutes. It is accompanied by pain and convulsions.
States in the US which have adopted the Death with Dignity act have devised a cheaper alternative to Secobarbital and Pentobarbital. This consists of the drugs
- Diazepam 1G
- Digoxin 50mg
- Morphine 15G
- Propranolol 2G
The combo of digoxin and propranolol is cardiotoxic, while diazepam and morphine should act as a anaestethics and analgesics, perhaps creating respiratory depression. It has been used with reported success on a large number of terminally ill patients. As with all cocktails, it should be used with an antiemetic regimen. The ingredients of this cocktail may be far easier to come by than barbiturates.
Fentanyl is about 100 times as potent as morphine.
"[...] 10 mg of Fentanyl is equal to almost a gram of morphine. This would lead to fatalities in all but the highest of opiate tolerance users."
A common side effect of opiates is nausea and vomiting. An antiemetic might help. Which antiemetic effectively suppresses opiate nausea?
Oral generally has lower potency. Snorting may have higher potency and also avoid rejection when vomiting. How effective is an empty stomach to avoid vomiting?
Injection would eliminate the rejection of oral ingested opiate. i.v. injection would act fastest and strongest.
Fentanyl patches have been smoked  so pure fentanyl should be smokable.
Death occurs by respiratory suppression while unconscious and may take hours.
Fentanyl is offered for bitcoins on alphabay, a darknet market accessible via the tor anonymity network. Take care not to buy from a scammer (if you do you may get all or some of your bitcoins back). Take care not to use a fake alphabay address leading to a fake market site. The addresses listed in https://www.reddit.com/r/DarkNetMarkets/wiki/superlist#wiki_alphabay are probably correct. Shipping across borders is more risky (drug trafficking is highly illegal in most places), but the small amounts needed may well get unnoticed, especially if the vendor uses good stealth.
Carfentanil is about 100 times as potent as fentanyl, but has a higher therapeutic index than fentanyl, so the lethal dose is probably higher than 1/100th the lethal dose of Fentanyl. Carfentanyl is not licensed for use in humans as there are other drugs with better therapeutic properties, therefore the lethal dose is unknown and claims for the lethal dose vary widely. The lethality of carfentanil is well established, though, as there are numerous deaths of users of low quality heroin that has been laced with carfentanil. A good lethal dose is probably somewhere from 1 to 10 mg.
Otherwise carfentanil is similar to fentanyl for the purpose of suicide.
Hydrogen sulfide, H2S, is a highly toxic gas smelling like rotten eggs. Concentrations over 1000 ppm (0.1%) cause immediate collapse with loss of breathing, even after inhalation of a single breath.
It can be prepared by mixing sulfides, e.g. sodium sulfide, Na2S, with acid.
Calcium polysulfide (lime sulfur) has been prepared by heating and stirring calcium hydroxide, Ca(OH)2, with sulfur powder, S. It is a comparatively weak source of H2S, but has been used successfully. It may be available as insecticide in hardware stores.
Iron sulfide, FeS, can be prepared by heating a well mixed mixture of 55 g fine iron filings or powder and 32 g sulfur powder till it ignites, e.g. in a test tube. Excess sulfur may create more pyrite, FeS2, which may be less reactive with acid. The resulting iron sulfide should be crushed to a powder so it will react well with acid.
Sodium sulfide, Na2S, is very effective. It may be available to make old looking photographs, but due to it's toxicity it may be unavailable.
Sulfuric acid (battery acid) is a good choice to liberate H2S from sulfides, as it does not evaporate. Hydrochloric acid, HCl, works, too, but in concentrated form (35%) it may release HCl vapors, which irritate the eyes and respiration. Vinegar or citric acid work, too, but more slowly.
Goggles can be used to avoid eye irritation by acid or H2S.
1000 ppm is 1 liter H2S per m3, equivalent to 3.6 g FeS or 3.2 g Na2S. The amount of calcium polysulfide is not well defined. Using more than needed, e.g. 10 times as much, may compensate for low quality sulfide (e.g. FeS), slow reaction, leaks or uneven distribution of the H2S.
Warning signs help avoid other people entering the toxic area.
Phenobarbital combo cocktailEdit
The US Death with Dignity act experts came up with this cocktail to circumvent the high cost of Secobarbital and pentobarbital.
- 20 g Phenobarbital
- 20 g chloral hydrate diphenhydramine
- 3 g morphine sulfate
Due to the high amount of drugs to ingest (43 g) and the extreme bitter taste, particularly of the caustic choral hydrate, this cocktail, while lethal, was not well received by patients and volunteers in euthanasia. It has since been superseded by the DDMP cocktail.