Cyanide exposure can happen occupationally or in low levels from inhaling cigarette smoke—or from being poisoned by someone out to get you. The effects are fast and can be deadly. But because cyanide is metabolized quickly, it can be difficult to detect in time for an antidote to be administered. Now, in an animal study in ACS’ Chemical Research in Toxicology, researchers report a new precise and accurate biomarker of cyanide exposure.