We’ve all had bad days at the office. Reed Smith commercial real estate partner Steven Regan, it seems, had one out of the office last week. And now the Am Law 100 firm is trying to make amends.

On October 15, Regan, who is based in the firm’s Pittsburgh headquarters, took to Twitter to opine on the U.S. Supreme Court’s decision to hear challenges to Environmental Protection Agency regulations related to greenhouse gas emissions.

As first noted by Above The Law, Regan—presumably thinking he was communicating with an official Supreme Court Twitter account, but instead directing his message to the Twitter handle linked to the High Court-watching SCOTUSblog—tweeted “@SCOTUSblog – Don’t screw up this like [Affordable Care Act]. No such thing as greenhouse gas. Carbon is necessary for life.”

The trouble began when SCOTUSblog replied with a sardonic two-word tweet: “Intelligent life?” To that, Regan offered an angry “Go f@ck yourself and die.” (SCOTUSblog capped the exchange with an extra shot of sarcasm: “Being an expert climatologist/real-estate attorney is very stressful. Breathe.”)

Though Regan, who was elevated to the Reed Smith partnership in 2007, deleted his Twitter account shortly after sending out the offending tweet, the 1,800-lawyer firm recognized that the five-word outburst merited an official response.

“The posting of offensive commentary or language on social media is inappropriate and inconsistent with Reed Smith’s social media policy,” the firm said in a statement initially given to the U.K. blog Roll on Friday and provided Monday to The Am Law Daily. “We are addressing this matter internally.”

The freewheeling, unfiltered nature of Twitter presents challenges for those in the legal profession who use it. The Am Law Daily has reported in the past on the problems some Am Law 100 lawyers have encountered on the social networking site and microblogging site. The American Bar Association also issued guidelines earlier this year warning judges to be mindful of the way they conduct themselves on social media, according to sibling publication The National Law Journal.

Reed Smith has previously shown that it is sensitive to how its attorneys use Twitter. The firm once sent its senior lawyers to “Tweet School” to learn about the social medium’s potential perils, according to a 2010 report by British newspaper The Guardian. Around the same time, sibling publication Corporate Counsel published a column by Reed Smith media and entertainment industry cochair Douglas Wood laying out the five steps lawyers and large firms can take to limit social media risks.

Regan did not immediately reply to The Am Law Daily’s request for comment on Monday. An email sent to him at his Reed Smith account by Above the Law last week yielded an autoreply message saying he was out of the office attending a family funeral.

An obituary for a Joan Regan, 74, appeared last week in the Pittsburgh Post-Gazette. A source familiar with the matter told The Am Law Daily the she was Regan’s aunt and that he was at the funeral home for her services when he sent his ill-advised tweet.