Four American airlines suspended flights to and from Mexico City on Thursday thanks to an explosion from the Popocatepetl Volcano.

While not a full eruption, Popocatepetl spewed a plume of ash high enough to disrupt international air travel. The volcano has been active most of the year but this is the first time that it has stopped flights.

The airport claimed that operations were normal and that no Mexican airlines stopped flights, however, AeroMexico suspended operations briefly on Thursday as well due to the ash in the air.

The airport had over 174,000 takeoffs and landings in the first six months of 2013.

Ash can clog the engines of planes causing a fatal engine shutdown.

Officials refused to raise the volcano’s alert level from the second highest designation declaring they don’t believe a full eruption is likely to happen. However, ash began to fall on communities near the volcano, an increase in activity from previous activity.