While urban trauma is commonly typified by penetrating interpersonal trauma that includes gunshots and stabbings, blunt interpersonal violence follows closely behind in frequency in the USA. Nonetheless, most urban trauma centers in the USA and Canada evaluate and care for more patients who are bluntly injured compared to those with penetrating trauma as a result of their regional resource status leading victims of falls and motor vehicle crashes to be transported from the scene or after stabilization at a less well-equipped medical facility.

Unlike urban trauma, terrorism often leads to both penetrating and blunt injury in the same patient [13]. This circumstance derives from the common occurrence of explosive devices such as improvised explosive devices (IEDs), suicide vests packed with explosives such as C4 (cyclotrimethylenetrinitramine) or Semtex (RDX [research department explosive]), an explosive nitroamine, and PETN (pentaerythritol tetranitrate) coupled with intentionally placed shrapnel such as ball bearings, screws, nuts, bolts, and the like, as well as secondary explosions from intentionally placed and delayed explosive devices, vehicles, fuel lines, or fuel depots. Such explosives lead to penetrating injury within the blast zone and blast effect within the blast radius; individuals may be thrown into stationary objects or mobile objects may be explosively moved into individuals [13].

Blast effect is a concussive injury derived from blast pressure measured in pounds per square inch (psi) during the rapid overpressure phase of the explosion [13–15]. For example, an overpressure of 1 psi leads to a maximum wind speed of 38 mph, while an overpressure of 10 psi creates wind up to 294 mph leading to severe damage to concrete structures and death in the majority of individuals exposed to the overpressure wave [16]. While military organizations are well acquainted with such injuries, civilian law enforcement and EMS may benefit from specific preparation including focused education, training, and resource management (see Chap. 27, Critical Incident Team Dynamics and Logistics).

No list of terror-related injuries is complete without specific mention of nuclear, biologic, and chemical (NBC) injury. Of the three, the first and last appear more readily realized by terrorist organizations due to the seemingly more limited availability of biologic terror agents such as weaponized anthrax or small pox in comparison to nerve agents or radioactive waste to manufacture a “dirty bomb.” The essential feature of NBC terrorism is that its events may be difficult to initially detect (other than a bomb explosion) and result in significantly worse effects due to the delayed reaction of responders who may not be adequately prepared for or protected from such threats [17, 18]. These injuries are discussed further in Chaps. 31 and 32. Additionally, such an event has the unfortunate by-product of creating fear of another such attack, leading to the notion that there is no safe refuge, perpetuating a culture of fear—a prime goal of terrorism.

Nonetheless, in the event of an NBC terrorist attack, the availability of appropriate personal protective gear is critical to protect first responders who arrive to evacuate and care for the victims of the incident [17]. Microbe biohazard protection is provided by the appropriate biohazard gear (biohazard level I–IV suits), while chemical and biologic protection is provided by gear including the military mission-oriented protective posture suits (MOPP suits 0–4) [19]. The availability of upper level gear may be limited outside of special facilities, and high-level suits are not commonly available even at major medical facilities, including regional resource trauma centers. Accordingly, a close working relationship with local military resources is essential in bringing suitably trained and equipped individuals to an appropriate location. Little, if any, nuclear radiation protective gear is readily available outside of specialized agencies and their designated protective details such as those at the Lawrence Livermore National Laboratory (https://​www.​llnl.​gov) and investigative and clean-up crews from the Nuclear Regulatory Commission (www.​nrc.​gov) and the National Nuclear Security Administration (www.​nnsa.​doe.​gov).

The terror attack on US soil on 9/11 marked a major change in US policy as terror firmly landed in North America, initiating the “Global War on Terror” [20]. Instead of supplanting a country’s governmental infrastructure, or unseating its political leadership to establish new rule, or driving out an invading force, terrorism shifted to coordinated attacks performed by small teams of terrorists. While structures were destroyed, the primary impact was on people and their view of the government. The small units, termed “cells,” operate both as part of a coordinated structure and independently [6]. Some may be in place for a short period of time prior to their specified activity, while others may remain dormant for long periods of time and are dubbed “sleeper cells” [6]. Thus, terrorist activities became personally focused instead of government or country focused.

The rise of social media and the widespread use of the Internet as a communication tool as well as an enabler of daily activity have afforded multiple opportunities for cyberterrorism [21]. Such activities span network disruption and identity theft and lead to organization member recruitment and have resulted in an expansive need for law enforcement capabilities [21]. Even small police departments support electronic expertise in crime solving and as such complement cyber policing that is performed by federal agencies such as the National Security Agency, the Federal Bureau of Investigation, and international agencies that include the Central Intelligence Agency [21].

Domestic terror events such as the Texas bell tower shootings that occurred in 1966 have resulted in the formation of Special Weapons and Tactics (SWAT) teams, as championed and refined by the LA County Sheriffs’ and Police Departments, and have flourished. In fact, since the 1970s, SWAT teams have increased by 80 % encompassing urban and suburban terror events spanning (but not limited to) barricaded hostage/suspect, riots, gang warfare, dignitary protection, and high-risk warrant service [22]. Driving the development, training, and outfitting of local SWAT teams is the need to respond to the changing demographic and advanced, high-powered equipment of perpetrators of violent crimes. Suspects and organized criminal elements have ready access to body armor and high-performance weapons as a result of military surplus obtained both legally and illegally. Additionally, increasing numbers of perpetrators of violent crime may have served as members of the armed forces and received specific weapon and tactical training [23]. Therefore, local police departments need to be able to respond to a host of different events forcing a metamorphosis from community-based policing to a threat matrix-based response. The transition has often been termed the “militarization” of local police forces and is typified by the inclusion of military relevant firearms, body armor, communications gear, training tactics, sound and light diversionary devices [24], and up-armored vehicles such as the Lenco BearCat, a mission-specific personnel carrier with both high-powered firearm and explosive device resistance. Some civilian departments in cities with frequent SWAT activations have begun investing in mine-resistant armored personnel (MRAP) carriers identical to those in service in Iraq and Afghanistan.

Similarly, instead of standard community policing where apprehending criminals constitutes approximately 10 % of total police work, departments are now devoting increased time and resources to elements that include active shooter scenario training [24]. Furthermore, and in a fashion parallel to that of the military, police officers are increasingly trained in self- and buddy aid using concepts and tactics borrowed from the Tactical Combat Casualty Care (TCCC) approach advocated initially by the Naval Special Warfare Command [25]. Recognizing that the patrol officer is likely to be the first responder to urban trauma or terror acts, this officer’s capabilities need to be enhanced and reinforced to increase the likely survival of the officer and those whose lives the officer has sworn to protect [25].

Such needs have also driven increased interagency collaboration with other law enforcement agencies including but not limited to state police; US marshals; Alcohol, Tobacco, Firearms; Drug Enforcement Agency; FBI; US Secret Service; and the National Guard as needed [26]. Since communication is key to such activities, the USA has developed fusion centers under the aegis of the Department of Homeland Security that are designed to funnel key and actionable intelligence to appropriate agencies within a specified territorial domain designed to disrupt potential or validated terrorist threats. Integrated domains include state, local, tribal and territorial, as well as private sector partners (www.​dhs.​gov/​state-and-major-urban-area-fusion-centers) [27]. Such communication is key to protecting and preserving national security by establishing and improving an information-sharing environment to help counter violent extremism.

Medical care as part of an organized trauma system began in the 1970s and continues to be refined today. In general, urban emergency medical services combine ground and rotary wing air ambulance transport into a working network that embraces support from both the local fire department and the local police department. Rural trauma systems may fold in aid from other agencies including the US National Park Service (www.​nps.​gov) and in Canada, the Royal Canadian Mounted Police (www.​rcmp-grc.​gc.​ca). Of necessity, the EMS response to urban violence is reactive in nature rather than preemptive. Nonetheless, despite the close working relationship with local law enforcement, only few areas of crossover have blossomed that leverage the capabilities of EMS with law enforcement.