HOUSTON – A flight bound for Mexico that took off from Houston was forced to return for a rather unusual reason – volcanic ash.

United Airlines flight 1088 took off from George Bush Intercontinental Airport around 11:52 a.m. bound for Mexico City, Mexico, according to the flight tracking website FlightAware.

The plane turned around shortly after crossing into Mexico and landed back at Bush Airport shortly after 2 p.m.

A United Airlines spokesperson said the flight was diverted back to Houston due to low visibility from volcanic ash.

“United flight 1088 returned to Houston because volcanic ash caused poor visibility in Mexico City,” a spokesperson said KPRC 2. “The health conditions have since improved and the flight will depart again soon.”

Data from FlightAware shows that the flight took off from Houston for the second time at 16:04 and landed safely in Mexico City, Mexico at 18:31 local time.