The envelope never made it to Judge Arthur Engoron, but caused an emergency response at the courthouse.

Judge Arthur Engoron, who handed down a $355 million ruling against former President Donald Trump in his civil fraud trial, was sent an envelope containing white powder on Wednesday, causing an emergency response at his New York City courthouse, a source with direct knowledge of the incident confirmed to NBC News.

The judge and his staff were not exposed to the substance — his mail is pre-screened on a daily basis and was intercepted before it reached him, the source said. A court officer opened the letter and powder fell out, according to the New York Police Department, exposing the officer and another court employee to the substance, the source said. The New York City Fire Department said the two refused any medical treatment. The threatening letter was first reported by ABC News.

The threat is far from the first against the judge. Police on Long Island responded to a bomb threat at his home last month, hours before closing arguments in the Trump trial were scheduled to begin.