The outdoor Olympic diving pool, which turned a startling shade of green Tuesday, is now closed. It reportedly smells like farts and may be causing eye itchiness among athletes.

Since Tuesday, Olympic organizers have repeatedly assured athletes and fans that the pool is safe and that the situation was under control. Rio organizing committee spokesman Mario Andrada told reporters on Wednesday that “the pool should go back to its classic blue color during the day.”

That clearly didn’t happen. Instead, reports trickled in that the adjacent pool used for water polo and synchronized swimming also began to turn green.

The cause of the emerald tides is still murky. Officials have discussed running out of an unnamed chemical used to treat the pool, algal blooms, too many people using the pool, and a pH imbalance. All of those may be factors. It’s conceivable that the organizers ran out of a chemical, such as muriatic acid, used to balance the pH of the pool, normally kept around seven, and wound up with a higher, alkaline pH. With the acidity out of whack, the disinfecting power of the chlorine would decrease and give algae a chance to get a foot in the door. When combined with hordes of microbe-toting swimmers and warm temperatures, all of this could lead to a jade lagoon.

However, if the cause is known, it’s unclear why the situation hasn’t been remedied yet. And if the disinfection level was lowered, it would open the door to viruses and bacteria as well. That wouldn’t jibe with officials’ confidence that the waters are safe.

Meanwhile, the women’s three-meter springboard prelims are planned to take place in the green diving pool today.

The eerie pool water is another drop in the bucket of health concerns at the Rio Olympics. Athletes competing in outdoor water sports have already been subjected to sewage, superbugs, and pollution.