Low-flying government planes, bomb-sniffing dogs, magnetometers, high-tech mobile command centers, SWAT officers, police horses or robots will all be a part of the massive annual security effort that comes with hosting the Super Bowl, which has long been considered a potential terrorist target.

League officials say that every year is unique and that plans change based in part on advances in technology. "We do have experience putting on large-scale events … we've been planning specifically for this Super Bowl for the last three years,” said NFL spokesman Brian McCarthy. "So we've engaged multiple agencies on the federal, state and local level to come up with a plan that continues to evolve.”

While there are no discusions of specific threats or estimated security costs, McCarthy said the NFL anticipates spending between $5 and $6 million on security.

That figure includes the hiring of outside security firms, and it is higher than what the league has spent on past Super Bowls. McCarthy said the higher cost is not because of any specific threat, but is due to the "size and complexity of venues” in North Texas.

Earlier this week an Environmental Protection Agency plane flew low over parts of Dallas and Fort Worth to take base-line readings as part of ongoing air quality monitoring for changes that could signal some type of chemical attack on the region.

The FBI will bring in about 200 additional agents who are trained to handle active shooters, bombs, and other hazards related to chemical, biological, radiological or nuclear threats.

Bomb detection dogs from the Bureau of Alcohol, Tobacco, Firearms and Explosives are sweeping the Dallas Convention Center, site of the NFL Experience, and Sundance Square in Fort Worth, site of ESPN's set.

Another top security priority is the ESPN set, with programming scheduled to begin early Monday morning and run through Sunday night. ESPN will hire off-duty officers to work security for the set itself, while on-duty city police will be heavily staffed throughout the rest of downtown.

Fans who have a ticket to the Feb. 6 game will also experience a new level of security. A detailed list of prohibited game-day items will be released next week, McCarthy said. But he said it will include typically banned items, such as fireworks, camcorders, umbrellas, strollers and beach balls. Every fan entering the stadium will be subject to a magnetometer wand and "light pat-down,” McCarthy said.