SAN FRANCISCO — Google fired one of its engineers, Blake Lemoine, on Friday, more than a month after he raised ethical concerns about how the company was testing an artificial intelligence chatbot that he believes has achieved consciousness.

A Google spokesman, Chris Pappas, said Mr. Lemoine, a senior software engineer in its Responsible A.I. organization, “chose to persistently violate clear employment and data security policies that include the need to safeguard product information.”

The company, which denies that its chatbot language model is sentient, had placed Mr. Lemoine on paid leave in June. Mr. Lemoine confirmed his dismissal in a text message on Friday, and said he was meeting with lawyers to review his options. The firing was first reported by the newsletter Big Technology.

Mr. Lemoine caused a stir last month when he told The Washington Post that he believed Google’s Language Model for Dialogue Applications, or LaMDA, was sentient — unleashing fears that A.I. was moving closer to a dystopian sci-fi film and a raucous debate over whether a computer program can really have a soul. His suspension also led to conspiracy theories about whether it was part of a cover-up by Google.

For Google, it was another in a line of homegrown controversies about the ethics and role of its A.I., an area of technology on which the company has staked its future.

Mr. Lemoine’s contention that LaMDA is sentient has been criticized by the company and many other A.I. experts who have said these types of chatbots — software that simulates a text-based conversation with another human, often used for customer service — are not advanced enough to be conscious.

“If an employee shares concerns about our work, as Blake did, we review them extensively,” Mr. Pappas said. “We found Blake’s claims that LaMDA is sentient to be wholly unfounded and worked to clarify that with him for many months.”

Besides taking his concerns to the media, Mr. Lemoine said in June that he handed over documents to a U.S. senator, whom he hasn’t identified, claiming that they provided evidence that Google and its technology engaged in religious discrimination.