Zola died on 29 September 1902 of carbon monoxide poisoning caused by an improperly ventilated chimney. His funeral on 5 October was attended by thousands, according to The New York Times. Dreyfus initially had promised not to attend the funeral but was given permission by Mme Zola and attended.
His enemies were blamed for his death because of previous attempts on his life, but nothing could be proved at the time. Expressions of sympathy arrived from everywhere in France; for a week the vestibule of his house was crowded with notable writers, scientists, artists, and politicians who came to inscribe their names in the registers. On the other hand, Zola's enemies used the opportunity to celebrate in malicious glee. Writing in L'Intransigeant, Henri Rochefort claimed Zola had committed suicide, having discovered Dreyfus to be guilty.
Zola was initially buried in the Cimetière de Montmartre in Paris, but on 4 June 1908, just five years and nine months after his death, his remains were relocated to the Panthéon, where he shares a crypt with Victor Hugo and Alexandre Dumas.
In 1953, an investigation ("Zola a-t-il été assassiné?") published by the journalist Jean Borel in the newspaper Libération raises the idea that the death of Émile Zola might be a murder rather than an accident. It is based on the revelation of the Norman pharmacist Pierre Hacquin who was told by the chimney sweeper Henri Buronfosse that the latter intentionally blocked the chimney of the apartment of Émile Zola in Paris ("Hacquin, je vais vous dire comment Zola est mort. [...] Zola a été asphyxié volontairement. C'est nous qui avons bouché la cheminée de son appartement.").