Google didn’t violate labor laws by firing engineer James Damore for a memo criticizing the company’s diversity program, according to a recently disclosed letter from the US National Labor Relations Board. The lightly redacted statement is written by Jayme Sophir, associate general counsel of the NLRB’s division of advice; it dates to January, but was released yesterday, according to Law.com. Sophir concludes that while some parts of Damore’s memo were legally protected by workplace regulations, “the statements regarding biological differences between the sexes were so harmful, discriminatory, and disruptive as to be unprotected.”

Damore filed an NLRB complaint in August of 2017, after being fired for internally circulating a memo opposing Google’s diversity efforts. Sophir recommends dismissing the case; Bloomberg reports that Damore withdrew it in January, and that his lawyer says he’s focusing on a separate lawsuit alleging discrimination against conservative white men at Google. NLRB records state that its case was closed on January 19th.

“So harmful, discriminatory, and disruptive as to be unprotected.”

In her analysis, Sophir writes that employers should be given “particular deference” in trying to enforce anti-discrimination and anti-harassment policies, since these are tied to legal requirements. And employers have “a strong interest in promoting diversity” and cooperation across different groups of people. Because of this, “employers must be permitted to ‘nip in the bud’ the kinds of employee conduct that could lead to a ‘hostile workplace,’” she writes. “Where an employee’s conduct significantly disrupts work processes, creates a hostile work environment, or constitutes racial or sexual discrimination or harassment, the Board has found it unprotected even if it involves concerted activities regarding working conditions.”

Damore’s memo, titled “Google’s Ideological Echo Chamber,” contended that Google’s diversity efforts were misplaced because they ignored women’s biologically driven disinterest in technology. It includes many claims, which have previously been dissected in detail online. But Sophir focuses specifically on Damore’s “statements about immutable traits linked to sex — such as women’s heightened neuroticism and men’s prevalence at the top of the IQ distribution.” These statements were “discriminatory and constituted sexual harassment, notwithstanding [Damore’s] effort to cloak [his] comments with ‘scientific’ references and analysis,” she writes. Moreover, she says Google “carefully tailored” its reasons for firing Damore, limiting them to unprotected portions of the memo.

Some legal experts suggested that Damore might have a solid legal complaint, if he could argue that he was discussing working conditions. But that apparently wasn’t a strong enough case for the NLRB — and Damore will be making an arguably tougher one in claiming that Google is systematically biased against white men.

Al Latham, a partner at Paul Hastings LLP — which represented Google in the case — said that “we are gratified that the NLRB General Counsel found that Google acted lawfully in not allowing this employee to create a hostile work environment.”

Update February 19th, 9AM PT: Added statement from Paul Hastings.