As part of preparations for Super Bowl XLV, low-flying planes will be doing aerial surveys around North Texas.
The Environmental Protection Agency is using twin-engine propeller planes to fly as low as 500 feet.
The survey comes in response to a request by the State of Texas for the EPA to assist in environmental monitoring activities during various events associated with the Super Bowl.
The environmental monitoring data gathered from the aerial surveys will be utilized by federal, state and local agencies for preparedness activities.
"We're trying to get a baseline figure over the next week to compare with what might happen the day before the game day or game day in the event of some chemical, radiological or biological event," explained Tarrant County emergency management coordinator Melissa Patterson.
She said the aircraft is not here in response to a specific threat. In fact, it's been used for many major events that draw large crowds.
The EPA said its specialized plane is often used during natural disasters to detect chemical leaks, such as when hurricanes hit refineries or chemical plants.
It was also deployed for the BP oil spill in the gulf.
In this case, Patterson said it's simply an added layer of security we haven't seen before.
As the crew of the twin-engine aircraft conducts their survey, they will fly in a series of straight lines at a low altitude, between 500 and 2,800 feet.
The aircraft will fly slowly, about 115 mph. Surveys should take about 30 minutes to one hour to complete.
The aircraft will be marked "U.S. EPA" underneath the wings for identification.