Guns N’ Roses guitarist Slash’s stepdaughter Lucy-Bleu Knight’s cause of death has been revealed. The Post can exclusively report that the 25-year-old died from hydrogen sulfide toxicity. The manner of her death is suicide, confirmed by the Los Angeles Medical Examiner’s Office on Thursday.

Hydrogen sulfide is a poisonous, flammable gas that can be toxic to humans. Symptoms of acute exposure to the gas can include nausea, headaches, delirium, disturbed equilibrium, tremors, convulsions, and skin and eye irritation, according to the Centers for Disease Control and Prevention website. High exposure can cause rapid unconsciousness and death.

“Ms. Knight was found unresponsive in a private residence on July 19 by law enforcement conducting a welfare check. Death was pronounced at 1500 hours,” the coroner’s office told The Post.

“An examination was performed by a deputy medical examiner on July 22. The cause of death was certified on August 29.” Knight’s cause of death was initially deferred as additional testing was required.

Slash, aka Saul Hudson, 59, shared news of Knight’s death on Instagram. In his post, Slash described Knight as “an incredibly talented artist, a passionate dreamer, and a charming, lovable, sweet soul.” He added that she “passed away peacefully.

” The rock and roll legend considered Knight a stepsister to his biological children: sons London, 22, and Cash, 20. Slash asked for “privacy” and that “social media speculation be .