EGLIN AIR FORCE BASE, Fla. -- Four students gathered near several cluster munitions stuck nose-down into the ground. They were conferring on how best to flip over a piece of air-dropped dispenser without risking injury from any unseen bomblets hidden underneath. (This was soon done with a rope and shovel, together forming a lever that a student could pull from afar.)
A few miles away, several students clutched watches while testing a green strand of time fuze. They were clocking the rate at which it burned so they could set up a precisely timed demolition later in the morning.
In a third patch of forest, Pvt. Kevin A. Stanley, 20, crouched with Airman First Class Joshua P. Oliver, 21, and studied a temporary mystery: the precise identification of a shell that had failed to explode. Was it Russian? Bulgarian? White phosphorous? High explosive? Something else?
The projectile body was rusted, but the underside of its fuze still carried metal stampings in Cyrillic. The men crawled forward with instruments resembling dental mirrors, trying to read the unfamiliar letters without touching the round and possibly causing it to burst.
Their assignment was to document as many details as possible -- the number of rotating bands, the shell's length and diameter, the paint finish and much more -- and then consult a classified database of global munitions to make the identification. The database would then provide instructions on how to make the weapon safe, which would be the exercise's next step.
These were the nearly simultaneous scenes playing out last month at an American military school that has quietly produced a group of service members in extraordinarily high demand: explosive ordnance disposal techs.
The wars in Afghanistan and Iraq have exposed a new generation of Americans to explosive hazards, from falling rockets and mortar rounds to the makeshift bomb, which takes a dizzying array of forms.
This command, which is formally called Naval School Explosive Ordnance Disposal and run by the Navy on an Air Force base, is neither strictly naval nor for the Air Force, as its name and location might suggest. It is a four-service academy that has become remarkably busy. In 2004, as the use of improvised bombs against American troops spiked, this school trained 600 students. This year, its officers say, the school will train 1,800.
Its approach is atypical. Enlisted service members and officers train side by side in the same classes, learning the same skills. This is in part because ordnance knows no rank. Each student in the 143-day basic course studies -- and must pass -- identical technical exams.
The school also does more than produce techs ready for American military units.
Many techs serve long careers in uniform. Others move on after a tour and take their skills to federal or other law enforcement agencies. Others return to conflict areas for private firms or as humanitarian de-miners, clearing roads, oil fields, farmland and homes of the lethal remnants of war.
Each of these lines of work can be unforgiving. So it is little surprise that given the breadth of instruction -- which covers everything from identifying every piece of ordnance in global production to disabling roadside bombs to clearing aircraft crash scenes of the ordnance still strapped to the crippled plane -- roughly a third of the students fail.
They are disenrolled, phase by phase, as the instruction becomes more complex. "The standard is high, and it is not up for discussion," said Capt. Joseph Polanin of the Navy, the school's commanding officer.
The reason, he said, is both obvious and unbending. "If you are rendering safe a particular kind of missile, and there are 16 steps for that, then you either do them precisely right or you fail, because if you do that wrong in the field, the results are catastrophic," he said.
As he spoke, explosions boomed several hundred yards away on a practice range. It is a frequent sound. While many of the school's training aids -- including the shell that Private Stanley and Airman Oliver were examining -- are inert, the students spend extensive time on ranges, learning to handle and rig explosives.
"We see visitors flinch here," said Lt. Nicholas M. Parker of the Navy, who leads the ground ordnance division. "But not students. They get used to that sound."
Outside Lieutenant Parker's office was a maze of problems. Every few yards was another shell, rocket or land mine, each waiting to be found, identified and dealt with by the students who move through.
Modern munitions work in many very different ways. Some explode upon striking a solid object. Others detonate after a set amount of time. Still others blow up when handled, or when a battery-powered fuze detects a disturbance of the nearby magnetic field, as when a vehicle drives near. Students are expected to learn them all, and how to defeat them.
In another section of the course, the forest was cluttered with aircraft bombs, air-dropped mines and cluster munitions, along with a few damaged aircraft, whose ordnance and other explosive devices, including ejection seats, were to be identified and disabled.
In still another patch of woods was an obstacle course. The obstacles were not for students, but for students to run robots through. This is the section that covers improvised explosive devices, or I.E.D.'s, the military's label for makeshift bombs.
On a recent Friday, one student, Specialist Rachael M. Martin of the Army, sat at a table while driving a Talon robot along the narrow course, putting it through sharp turns, climbing a ramp and staircase, and picking up golf balls and dropping them into an inverted cone.
She winced. "It is a lot harder than it looks," she said.
That remark might describe the entire school, which many of its graduates see as the center of a society unto itself. It is no accident that the school maintains the profession's memorial for techs killed in action.
The memorial stands in front of the school's main building. Its wall is engraved with nearly 300 names of explosive ordnance disposal techs. That tally was through the last memorial ceremony, held in the spring, when 18 names were added -- the most American disposal techs ever to die on duty in a year.
In the months since, even after the American military presence in Iraq has ended and as the presence in Afghanistan wanes, 12 more techs have been killed. This profession, once not often heard of, has become in the age of the makeshift bomb one of the most dangerous of all.
This article originally appeared in The New York Times.