Like many of the strange images that emerged from the Capitol siege last Wednesday, federal employees wearing what looked like space helmets only added to the confusion and horror of what was actually taking place.
During the attack, both Rep. Alex Mooney and Rep. David Trone tweeted photographs of themselves with the transparent head gear, which takes on the look of gas masks featuring black hardware, silver valves and red LED lights.
"I'm safe," read Mooney's tweet. "We've been equipped with escape hoods and we're being moved through the Capitol."
The personal protective gear is indeed called "escape hoods" (or "escape respirators"), according to Popular Science.
The purpose of the hoods is to "allow an untrained civilian to quickly and safely get away from an area that may have a chemical, biological, or even radiological or nuclear threat present."
"It's designed for a relatively untrained user, where you pop it on your head, and go," said Doug Durney, the product line manager for ILC Dover, the company that supplies the hoods. "There's no on-off button."
"When you open it from its case, it automatically comes on."
After a seal is made around the user's neck, both a HEPA filter and a carbon filter draws clean air into the hood. Air escapes through another valve on the unit, keeping the user safe from contaminants.
But only for a short time -- 30 minutes to be exact -- as the hood is intended to be donned quickly while the user immediately finds shelter from the dangerous area.
Members of Congress and federal employees had access to the hoods because they were stockpiled at the Capitol in the wake of the 9/11 attacks, per The Los Angeles Times. Over 20,000 units were shipped after five people died from the anthrax attacks centered on two U.S. Senators' offices back in 2001.