According to the Washington post, Musk is quoted saying to the employee, "That is no excuse. I am extremely disappointed. You need to figure out where your priorities are. We're changing the world and changing history, and you either commit or you don't."
The quotation comes from Elon Musk: Tesla, SpaceX and the Quest for a Fantastic Future, by business journalist Ashlee Vance. The book is due for release on May 19.
Musk called the quote "total BS," saying the book wasn't "independently fact-checked" and should be taken with a grain of salt.
A preview of the book published by the Post says that Musk and others were interviewed during the writing process.
The alleged comments were released as part of a list of the 22 "most memorable" quotes from the book, as chosen by the Post. Musk said that another quote, in which he allegedly described himself as having the mentality of a samurai, was also in need of correction.