WASHINGTON — U.S. industrial production slowed to a 0.4% gain in August as the shutdowns caused by Hurricane Ida curbed manufacturing activity.

Closures of petrochemical plants and petroleum refining along the Gulf Coast shaved 0.3 percentage points from output, the Federal Reserve reported today, which was just half the 0.8% increase recorded in July.

Industrial production covers manufacturing, utilities and mining. For just manufacturing, factory output slowed to a 0.2% gain, reflecting the hurricane impact, following a much stronger 1.6% increase in July. The August increase was led by a big gain in furniture production.

Manufacturing has been hobbled in recent months by snarled supply chains particularly in such areas as production of computer chips for cars.

Output at the nation’s utilities rose 3.3% in August while output in mining was down 0.6%.