Have the suicides begun?
https://www.dallasnews.com/business/american-airlines/2018/04/26/passengers-family-blames-american-airlines-death-after-flight-emergency
https://www.emedicinehealth.com/cyanide_poisoning/article_em.htm#what_are_the_signs_and_symptoms_of_cyanide_poisoning
Detection of cyanide poisoning can be difficult. The effects of cyanide ingestion are very similar to the effects of suffocation. The mechanism of toxicity occurs because cyanide stops the cells of the body from being able to use oxygen, which all cells need to survive.
The symptoms of cyanide poisoning are similar to those experienced when hiking or climbing at high altitudes, and include:
General weakness
Confusion
Bizarre behavior
Excessive sleepiness
Coma
Shortness of breath
Headache
Dizziness
Vomiting
Abdominal pain
Seizures
Typically, acute cyanide ingestion will have a dramatic, rapid onset, immediately affecting the heart and causing sudden collapse. It also can immediately affect the brain and cause a seizure or coma.