It appears that the Environmental Protection Agency was not the first federal agency to experience an employee poop problem.

Last year, managers at one of the EPA’s regional offices had to send a memo to staff reminding them not to defecate in the hallways. But there was another workplace pooping incident involving another federal agency decades earlier--and it remains an unsolved mystery.

The difference is that the earlier episode took place hundreds of thousands of miles from the earth’s surface, aboard the Apollo 10 spacecraft orbiting the moon in 1969 in preparation for the Apollo 11 landing, Vox reported recently.

As the Apollo 10 spacecraft circled the moon, mission Commander Tom Stafford made a sudden, distasteful discovery. “There’s a turd floating through the air,” he declared. This was, apparently, not an altogether uncommon phenomenon. Without going into too much detail, the plastic bag-based “fecal subsystem” deployed on long space flights had a less-than-perfect track record in capturing and containing excrement.

Indeed, an official NASA report on the subsystem noted that containing waste was particularly difficult:

The collection process required a great deal of skill to preclude escape of feces from the collection bag and consequent soiling of the crew, their clothing, or cabin surfaces. The fecal collection process was, moreover, extremely time consuming because of the level of difficulty involved with use of the system. An Apollo 7 astronaut estimated the time required to correctly accomplish the process at 45 minutes.

Upon discovery of the Apollo 10 fecal floater, Vox reported, the astronauts on the mission engaged in a rather spirited debate as to its origins:

“I didn’t do it. It ain’t one of mine.” “I don’t think it’s one of mine.” “Mine was a little more sticky than that. Throw that away.”

Minutes later, lunar module pilot Eugene Cernan exclaimed: “Here’s another goddamn turd. What’s the matter with you guys?”

While a modified version of the “he who smelt it, dealt it,” rule could conceivably apply in this case, it appears we’ll never know who bears responsibility for the soiling of Apollo 10.