TULSA, Oklahoma - Fire suppression foam accidentally covered several helicopters at the Oklahoma Army National Guard base in Tulsa Tuesday morning. The foam didn't cause any damage to the choppers and didn't cause any injuries.

The base is located next to Highway 169 at 46th Street North. 

A civilian contractor was testing the base's alarm and safety system and accidentally triggered the suppression foam equipment inside the hangars. The foam filled the hangars and buried ten Black Hawk helicopters, seven parked in the hangars and three on the ramp outside.

Osage SkyNews 6 HD pilot Will Kavanagh, who also flies the Black Hawk helicopters at the base, says the contractor tests the alarm and safety system periodically.

Kavanagh says the unit has 11 Black Hawks and only one of them escaped contact with the foam.

"It's hard to get to the shut off valve when you have 15 feet of foam in the hangar. Imagine being in the middle of the foam and trying to find your way around. It's like being in a fog bank without being able to see in front of you," Kavanagh said.

The Black Hawks are meant for war, so the cockpit doors that were covered in foam weren't damaged.

"All these things are very sealed and meant for harsh environments. Be it hot or cold temperatures, wind, dust and even water," he said.

The unit's Black Hawks are the UH-60M model which means they have high-tech instruments in their cockpits. The helicopters on the ramp were closed up so the foam didn't get inside, he said, but the choppers in the hangars were undergoing maintenance so access panels and even cockpit doors were open to the foam.  

He said the foam faux pas may have been inconvenient, but it was actually a great safety drill.

"It's a cool thing to see and it's really good to see how effective and how much volume is put out so quickly," said Will Kavanagh, Black Hawk pilot.

The chemicals aren't harmful to the environment, he said, and had another benefit: crews have to wash the aircraft every 30 days, so now they are good for another month.

Kavanagh said mechanics checked them all over Tuesday and they're all back on flight status. He said it turned out to be exactly like a big bath for the choppers.

Kavanagh said the contractor, SimplexGrinnell, cleaned up the foam from the hangar and the ramp.