#secondsfromdisaster #fullepisodes #shortfilm
Category
📺
TVTranscript
00:00The Alps, Europe's majestic wonderland, and deep inside is one of the world's longest
00:08tunnels.
00:10Every day it carries thousands of motorists in safety until an ordinary truck explodes
00:16into flames.
00:19The tunnel turns into a terrifying death trap in just 14 minutes.
00:24Now with cutting-edge computer technology, we reveal exactly what went wrong.
00:34Disasters don't just happen.
00:35They're triggered by a chain of critical events that unravel the fateful decisions in those
00:40final seconds from disaster.
00:47Europe, France, Mont Blanc.
00:54March 24, 1999, 10.30 a.m.
01:02The world's deepest tunnel, cut through solid rock, lies a mile and a half beneath Mont Blanc,
01:09Europe's highest mountain.
01:12It is a vital link between France and Italy, and truck drivers like it because it shortens
01:17their journey from seven hours to a mere 15 minutes.
01:22It also saves a climb through winding mountain roads.
01:29More than 5,000 vehicles use the tunnel every day, including tourists and locals.
01:41It's a fine spring morning as British trucker John Whitby heads for the toll on the Italian
01:46side.
01:47If you come up through the mountains towards the tunnel entrance, it's very picturesque,
01:51and then there's this little black hole in the side of the mountain.
01:55Prior to this particular day, I'd always been quite happy to go through the tunnels.
02:03Some use the tunnel for pleasure.
02:05Extreme skier Nicholas Borghi is heading from his home in Italy to the ski slopes of France.
02:11That day, the snow conditions were perfect.
02:17It is my passion to ski off-piste.
02:23We packed our ski boots and all our other gear in the car and drove towards the tunnel.
02:31When we got there, we paid our tolls and entered the tunnel as we'd done 1,000 times before.
02:46Usually it takes Borghi 15 minutes to drive through the tunnel.
02:50Today's journey will be different.
03:02Surely it's always dangerous to cross a tunnel, but nothing had ever happened before.
03:14As Borghi and Whitby drive through the tunnel from Italy to France, two independent control
03:20rooms monitor their progress, one on the Italian side and one on the French side.
03:32Until now, it's just another day in the tunnel, a tunnel that has carried more than 45 million
03:40vehicles since it opened in 1965.
03:43A remarkable feat of engineering, it took four years to blast through the solid rock
03:48of the Alps to create one of the longest tunnels in the world and one of the safest.
03:57Eighteen fire shelters are spaced every third of a mile throughout the tunnel.
04:02There are 77 emergency telephones with a dedicated rescue team at the French end and volunteer
04:08rescuers at the Italian end.
04:12Until March 24th, 1999, it's free of major incidents, as the teams have extinguished
04:18all previous truck fires without major casualties.
04:23But this is about to change.
04:2710.46 a.m., a 40-ton refrigerated truck arrives at the toll booth on the French side of the
04:38tunnel, one of the 2,000 that use the tunnel every day.
04:43Behind the wheel is Gilbert de Graaf, a 57-year-old Belgian driver with 25 years' experience.
04:5210.47.
04:54He enters the tunnel and reaches 37 miles per hour.
05:13His refrigerated rig is carrying an everyday load, nine tons of margarine and 12 tons of
05:19flour destined for a food factory in Milan.
05:28Other trucks and cars enter the tunnel behind him, and as always, 40 closed-circuit TV cameras
05:34monitor the progress of all vehicles.
05:3910.49.
05:43De Graaf's truck has been in the tunnel for two minutes, but neither he nor the closed-circuit
05:48TV cameras pick up the first signs of trouble.
05:54White smoke is escaping from behind his cab.
05:58De Graaf's truck is now a mile-and-a-half underground and over a mile into the tunnel.
06:07Unaware of the smoke, he continues his journey.
06:1210.50.
06:15The smoke increases.
06:21De Graaf is nearing the middle of the tunnel.
06:26Nine sensors run the length of the tunnel, feeding visibility information to the control
06:30rooms at both ends.
06:33When visibility is reduced by 30 percent, it triggers an alarm, but the smoke billowing
06:39from de Graaf's truck isn't that dense yet.
06:43At last, de Graaf notices.
06:46I looked at my side mirrors.
06:49I saw some smoke at the right side, but not much, so I drove on normally.
06:5510.51.
06:59De Graaf is more than three miles into the French side, and the situation is now far
07:04from normal.
07:05Oncoming cars and trucks can clearly see smoke from behind the cab.
07:10It passes under the trailer and swirls up toward the roof of the tunnel.
07:15Other drivers realize that something is wrong, and they try to get de Graaf's attention.
07:2110.52.
07:25Now the smoke is dense enough to trigger the tunnel's sensors.
07:30They raise an alarm in the French control room, but not the Italian one.
07:34Due to a false alarm, it was turned off the previous day.
07:39False alarms are not uncommon.
07:41At this stage, only the French tunnel operator hears the alarm, but doesn't know its cause.
07:48Meanwhile, the entrance tolls to the tunnel remain open, and vehicles continue to enter
07:55from both ends.
07:59Finally, Gilbert de Graaf can no longer ignore the smoke.
08:10As I drive, the smoke is increasing.
08:13I put on my hazard lights to warn the people behind and avoid an accident.
08:1910.53.
08:22He brings his truck to a halt.
08:23He is more than three and a half miles in, the halfway point of the Mont Blanc tunnel.
08:28I stopped slowly.
08:29I got out of the truck, and the smoke was much more noticeable.
08:33A line quickly forms behind him.
08:37I tried to grab hold of the extinguisher, but I didn't have time because the whole cabin
08:43was in flames.
08:44Suddenly, it explodes.
08:50De Graaf abandons his truck and runs towards Italy.
08:55Moving towards him, on the other side of the road, is Nicolas Borghi.
09:04I was halfway through the tunnel when I saw a glow far away.
09:10Then when I was 20 meters away, I saw a massive flame, and the truck driver running away.
09:19The line behind de Graaf's truck is growing.
09:2238 men and women are stuck in their vehicles, and none of them can see the danger ahead.
09:30But John Whitby, who is coming from the opposite direction, can.
09:33We looked down the tunnel and couldn't see anything but blackness.
09:38What we didn't know at that point was that the blackness was actually thick smoke.
09:47And that thick smoke is rapidly enveloping the vehicles stuck behind de Graaf's truck.
09:53Within seconds, the road tunnel could turn into a raging inferno.
10:02Seconds from Disaster will continue in a moment.
10:07We now return to Seconds from Disaster.
10:15A truck traveling from France to Italy in the Mont Blanc tunnel stops and bursts into flames.
10:21A line of vehicles comes to a halt behind it.
10:27Alarms trigger in the tunnel's control rooms, but operators don't realize the seriousness of the situation.
10:34They continue to allow vehicles to enter the tunnel from its two entrances in France and Italy.
10:4410.54. The truck has been on fire for one minute.
10:49Someone in the tunnel sees the smoke and uses the emergency phone at Shelter 22, almost 1,000 feet from the truck.
10:57It rings through to the Italian control room.
11:01The operator gets his first direct information that there is a serious problem.
11:06Immediately, the Italian and French controllers contact each other.
11:13Now they can clearly see the smoke on their monitors, but they can't see the truck.
11:19It's engulfed by the smoke.
11:25Realizing the danger, they close the tunnel to new vehicles at both ends.
11:33But for the 25 vehicles and 38 people who have already followed de Graaf's truck into the tunnel, it's too late.
11:41They're either driving towards the truck or they're stuck behind it.
11:5510.56. By now, thick black smoke is moving over the first of the trapped vehicles behind the truck towards France.
12:07But ahead of the flaming truck towards Italy, the smoke is spreading more slowly.
12:12One of the drivers coming from that direction is Nicolaus Borghi.
12:19I myself and the cars behind me were able to reverse till we reached a lay-by where we could do a U-turn and head towards the exit.
12:37In the Italian control room, an operator sees the fleeing vehicles and pumps in fresh air.
12:45But this increased airflow moves through the tunnel towards the fire and France.
12:50When air hits fire, it creates a problem.
13:00Like Borghi, John Whitby is also trying to escape.
13:06He stops a thousand feet from the inferno.
13:16But the tunnel is too narrow for his truck to turn.
13:19He has no choice but to abandon it.
13:22As he does, he looks back on the trapped vehicles.
13:26There must have been a lot of people that just did not stand a chance at all.
13:32It must have been absolutely horrifying for them.
13:36As Whitby makes his escape, the fire is burning fiercely, producing more and more thick black smoke.
13:4510.57.
13:48The fire has been raging for just four minutes, yet the killer smoke has already traveled a third of a mile towards France.
14:00The alarm reaches the tunnel's rescue team stationed at the French entrance, and a four-man team prepares to go in.
14:1010.58.
14:12The wall of smoke from the epicenter of the fire obscures the view of the closed-circuit TV cameras.
14:20And as the French rescue teams enter the tunnel, they don't know that 38 people are stuck in their vehicles behind the truck.
14:33For the drivers, the situation is horrific.
14:37Visibility is reduced to less than two feet.
14:40Panicked, some try to drive away.
14:46But the lack of oxygen kills their engines and their only means of escape.
14:52In desperation, some try to reach shelters, specially designed fireproof rooms located every third of a mile.
15:00But their quest is futile.
15:05It's a living nightmare.
15:12Most of those trapped are unconscious within minutes.
15:21It's now 11 o'clock.
15:28As the scale of the catastrophe grows, firefighters from the French town of Chamonix scramble to enter the tunnel.
15:39But they only travel two and a half miles before their vehicle is swallowed by smoke.
15:48Unable to turn around, they are forced to abandon it and seek shelter in a maintenance room, where they will remain for five hours.
16:02No emergency services manage to reach the center of the blaze.
16:08And now, the first rescuers enter from the Italian side, where the smoke is spreading more slowly.
16:14John Whitby is still by his truck when he sees them.
16:17The wail of sirens came down the tube and they screamed past us down into the darkness ahead.
16:27And they were sort of swallowed up by the smoke, actually.
16:31The Italian volunteer rescuers get within a thousand feet and one patrolman gets within 30 feet of the truck.
16:38But then a new danger forces them all to turn back.
16:41There were six explosions in rapid succession, which were just bang, bang, bang, bang, bang, very quick.
16:48They were very powerful explosions.
16:51Tires from the vehicles explode, sending deadly shrapnel flying.
17:01The tunnel wall shook with the force of the explosion.
17:05Within a minute or two of that happening, the fire brigade were back.
17:13As they retreat, the Italians rescue John Whitby and other drivers.
17:18Among them is Gilbert de Graaf, the driver of the truck that starts the inferno.
17:24They exit the tunnel on the Italian side, all making a miraculous escape.
17:3311-11.
17:40Italian firefighters enter the tunnel to tackle the blaze.
17:53Leading them is fire chief Dionigi Glari.
17:59We could see in the distance a wall of smoke that we tried to penetrate with our vehicle.
18:06But again, the smoke is too thick and Glari and his team are forced to retreat.
18:12They seek shelter in refuge number 24, one of the tunnel's fireproof rooms.
18:17Here, they'll be safe for two hours.
18:20But for these firefighters, the drama is far from over.
18:26They receive word that their colleagues are trapped.
18:29But where?
18:31Bravely, Glari and his team leave the safety of shelter 24 and venture into the smoke to
18:38try to find them.
18:44We were walking in the tunnel with one hand along the walls so as to find our way.
18:55Reaching the next refuge, we entered, looked around and found there was no one there.
19:04The conditions worsen and after ten minutes, the firefighters are forced back to shelter
19:0924.
19:10To their disbelief, the smokeproof room now offers them little protection.
19:20We saw smoke coming from the ventilation vents that should send clean air into the refuge.
19:25With their breathing apparatus running on empty, they are desperately short of air.
19:30Outside, the operation commander devises a plan.
19:33The trapped firefighters are told that beneath the road is a ventilation duct full of fresh
19:38air which may offer a means of escape.
19:41The problem is finding the door without getting lost in the smoke.
19:48To reach this doorway, we had to use an electrical extension lead that we tied to the door of
19:52the refuge and then went to look for the doorway.
19:57At the same time, more Italian firefighters are sent in through the ventilation duct to
20:02try to open the door from below.
20:08The moment they opened that door, that was the moment I glimpsed a possibility of escape.
20:18The rescuers become the rescued.
20:21After three hours, Glari and his team are able to escape through the ventilation duct.
20:30But what they don't know is that 38 people are still trapped inside the tunnel with temperatures
20:37exceeding 1,000 degrees.
20:441130.
20:49Thirty-seven minutes after the truck erupts in flames, the dense, deadly smoke now stretches
20:55for nearly four miles, filling the tunnel all the way to the French exit.
21:11Firefighters abandon all efforts to attack the flames.
21:16No one in the tunnel has a chance of survival.
21:23The fire is so ferocious, it burns for 53 hours.
21:31Only then can firefighters pick their way through the charred debris.
21:37They are horrified to discover the remains of the 38 trapped people.
21:43These pictures reveal the true extent of the tragedy.
21:49Those who survive, like Nicholas Borghi, are astonished at the fire's ferocity.
21:58More shocking is that the heat had melted the steel in the lorries.
22:01You could only see the basis of the lorries, the skeleton.
22:05What could have happened to those poor people left in there?
22:13The disaster takes everyone by surprise.
22:16How could such a catastrophe occur?
22:19How could an ordinary truck carrying an ordinary load of margarine and flour cause one of the
22:25worst tunnel disasters on record?
22:29From the moment the truck enters the tunnel, it takes just 14 minutes for 38 people to
22:34perish.
22:37Now we rewind the events of that fateful day and go deep into the investigation to reveal
22:44what really happened.
22:50Advanced computer simulation will take us where no camera can, into the heart of the
22:56disaster zone.
23:00A team of experts is assembled to investigate the fire.
23:04Using their data, we can piece together the deadly chain of events to find out what caused
23:10this terrible tragedy.
23:14The first mystery facing the experts is what starts the fire in the truck.
23:20They trace the truck's journey on its approach to the tunnel.
23:24This is where problems could first occur.
23:28Trucks frequently overheat on the long climb up to the tunnel entrance.
23:35Investigators examine the remains of the truck.
23:37Is there a fault with the FH-12 engine?
23:43After intensive tests, they find no conclusive evidence of overheating, then a breakthrough.
23:54Investigators find particles inside the engine that could only get there if the air filter
23:59had burned before the main fire.
24:03But how could the air filter have burned first?
24:07One theory is that a casually discarded cigarette from a passing vehicle enters the truck's
24:13air filter on top of the cabin.
24:17The cigarette travels down the filter, which catches fire.
24:23Particles then enter the engine, causing that to catch fire.
24:26Then the blaze starts.
24:28It's a strong possibility.
24:32Investigators then carry out an experiment on a similar truck in similar conditions.
24:38Although not conclusive, it proves that a cigarette butt entering the air filter could
24:43cause a fire.
24:45But that in itself is not enough to cause a tragedy on the scale of the Mont Blanc Tunnel
24:50Fire.
24:51How did this small fire turn into a raging inferno?
24:58Stay tuned.
24:59More Seconds from Disaster in a moment.
25:03And now, back to Seconds from Disaster.
25:10Deep in the Mont Blanc Tunnel, a minor fire suddenly spirals out of control.
25:15In 14 minutes, 38 people perish.
25:22Using advanced computer graphics based on official reports, we go deep into the investigation
25:28to unravel the deadly chain of events.
25:33Investigators believe it starts with a small fire smoldering in the engine beneath the
25:37cab.
25:38Fourteen minutes from disaster, de Groot enters the tunnel.
25:47But the fire only erupts after he stops and abandons his vehicle.
25:53Could the movement of air prevent the fire from taking hold?
25:57Experts know that truck fires can develop more quickly when vehicles slow down or stop
26:02because the supply of oxygen increases, which feeds the fire.
26:07Ed Gallia is a fire expert.
26:09There was a recent example where a bus had caught fire in an alpine tunnel and the bus
26:15driver continued driving, managed to get the vehicle through the tunnel to the other side,
26:21managed to evacuate the vehicle, and then the bus erupted in flames.
26:26Maybe if de Groot had continued driving, he could have made it to the end of the tunnel
26:30before the fire flared up.
26:34But he didn't.
26:38Seven minutes from disaster, he stops halfway through the tunnel.
26:43Almost immediately, the truck bursts into flames.
26:50But why did it spread so quickly?
26:55Beneath the refrigerated trailer, just feet from the flames, are the truck's diesel tanks.
27:02Investigators know that in previous truck fires, diesel is a contributing factor.
27:10Did diesel from de Groot's truck fuel the fire?
27:14De Groot's truck is carrying 145 gallons of diesel.
27:19This tank is only half full, so it can't be the cause of the rapid spread of fire.
27:34Investigators turn their attention to the contents of the refrigerated trailer.
27:38It's carrying nine tons of margarine and 12 tons of flour, a seemingly harmless load that's
27:44not even classified as dangerous goods.
27:48With little else to go on, they begin to experiment with the cargo.
27:57Here, a simple demonstration shows how one ton of margarine simulates the cargo.
28:03It's wrapped in polystyrene sheets, the same insulation material lining the refrigerated trailer.
28:11After just two minutes, it proves to be a highly combustible combination.
28:17In refrigerated vans, you have polyurethane, and when this burns, it produces a lot of heat.
28:26It burns, it can burn very rapidly.
28:28When the margarine melts due to the fire, it's an oil-based material, and it will also
28:34rapidly burn, producing quite a lot of heat.
28:37Margarine has a very high energy content.
28:40When melted, it's almost as dangerous as gasoline.
28:43Our experiment shows how dangerous things can be in the open air.
28:47But experts know that in the confines of tunnels, fires burn much more intensely because
28:52there are limited outlets for the heat to escape.
28:58To find out more, this research facility is conducting large-scale fire tests in an unused
29:04tunnel in Norway.
29:08Simulated trailers with various loads are set on fire to gauge the heat generated by
29:12trucks carrying typical loads like packing crates and furniture.
29:18The result is the world's highest heat release rating ever recorded in a tunnel fire test.
29:25But is margarine even more flammable?
29:27The Montblanc team calculates that the burning load of margarine may have rated even higher.
29:33The intensity of the fire on March 24, 1999, takes everyone by surprise, including Montblanc
29:40tunnel expert Jean Martinetti.
29:43The fire reached between 1,000 and 1,200 degrees.
29:47Nothing could withstand it.
29:49Everything melted, the ground, the concrete, the structure.
29:52It was completely unthinkable, a real crematorium.
30:02Investigators are shocked that a simple cargo of margarine and flour, not classified as
30:07dangerous, could produce a fire almost as powerful as an 8,000-gallon fuel tanker.
30:17But 14 other trucks are stuck in a half-mile line behind the first burning truck.
30:23Could these have contributed to the fire?
30:29The combined firepower of these trucks burning together takes the inferno to an unimaginable
30:34level of horror for the 38 trapped people in the tunnel.
30:39The vehicles that were involved in the fire had the energy content equivalent of about
30:44five to seven petrel tankers full of fuel.
30:51But for these vehicles to contribute to the inferno, the fire first had to spread to them.
30:57How did that happen?
30:59Three explanations emerge.
31:01First, the burning truck radiates heat and generates hot gases.
31:06In the confines of a tunnel, vehicles a great distance from the fire can ignite.
31:15Another way is that the vehicle that's on fire is leaking fuel, and it runs along the
31:20length of the tunnel.
31:23Yet another way is if the fire is very intense, your road surface itself catches fire, and
31:30then that will ignite the other vehicles in the tunnel.
31:38Investigators are not able to prove which of the three methods causes the fire to spread,
31:43but they do make another discovery.
31:46Fire is not the real killer.
31:50We found out later that people died in the cars before they could even open the doors
31:58and get out.
32:03So if fire isn't the killer, what is?
32:08We'll return with more Seconds from Disaster after this.
32:12You're watching Seconds from Disaster.
32:20A smoldering truck enters the Mont Blanc tunnel.
32:28The driver stops, and suddenly his truck explodes into flames.
32:40Investigators know that the driver manages to escape the inferno by running towards Italy.
32:46But 38 motorists behind his truck, back towards France, perish.
32:51Why?
33:01Investigators focus on the smoke given off by the fire.
33:04Without realizing it, John Whitby is a witness to this deadly wall of smoke.
33:09All we could see ahead was blackness about 200 meters from where we were stopped.
33:16It was just completely dark.
33:19We presumed that it was just lack of lighting, but it actually turned out to be the smoke
33:25from the fire.
33:27Seven minutes from disaster.
33:30Data gathered from sensors in the tunnel reveal that, in these minutes, smoke travels half
33:35a mile over the 25 gridlocked vehicles.
33:38The smoke travels 15 feet per second, nearly 10 miles per hour, creating a sudden loss
33:44of visibility down to a foot and a half.
33:48The trapped drivers have only seconds to decide whether to try to reach the safety of a shelter
33:53or remain in their vehicles.
33:55People probably believe that they're safe in their vehicle, that the smoke is not going
34:00to be too much of a problem, that the fire will be brought under control and they might
34:04as well stay in their car.
34:12Four minutes left.
34:15In the middle of the smoke, four cars do attempt to turn around.
34:22The tunnel is wide enough, so why don't they make it?
34:28Experts know that car engines need oxygen to work.
34:35The fire is consuming the oxygen and replacing it with carbon monoxide.
34:40Starved of oxygen, the vehicles' engines sputter and die.
34:45There's no way out.
34:47The fate for those who abandon their vehicles is equally bleak.
34:51They are overcome by smoke and other toxic gases before they reach the safe areas.
35:02Analysis of the scene reveals that the smoke contains cyanide, a gas that no one can survive.
35:11The smoke fills the French half of the tunnel so rapidly that none of the 38 trapped people
35:17stands a chance.
35:20Even the fittest individual couldn't outrun it.
35:28Fourteen minutes after the truck enters the tunnel, everyone behind the truck has perished.
35:47Investigators now turn their attention to the deadly smoke and why it moves towards
35:52France.
35:53Normally, air in the tunnel flows the other way, towards Italy.
36:03The tunnel operators can dramatically affect the airflow using the tunnel's ventilation
36:07system.
36:10Gigantic fans in plant rooms at both ends enable the operators to supply or extract
36:16air through ducts running beneath the road.
36:20The tunnel operation requires ducts to supply air, but in the event of fire, duct 5 is supposed
36:25to be set to remove the smoke.
36:29Did operators carry out the correct emergency procedure?
36:32Jean Martinetti has studied the official reports and knows the tunnel inside out.
36:37He is shocked by what he learns.
36:39When the fire occurred, on the Italian side, according to the reports, the Italian operator
36:45blew fresh air in instead of extracting it.
36:56The Italian tunnel operator sees motorists attempting to turn around.
37:02To aid their escape, he adjusts the ventilation settings and pumps in fresh air.
37:09The disruption of normal airflow plays a major role in the disaster, although the air blow
37:15in from Italy undoubtedly saves some lives, including John Whitby's.
37:28I realized how lucky I was.
37:3390% of the time, the smoke would have come the other way, to Italy, and I wouldn't be here now.
37:41But the air being pumped in from Italy moves the smoke towards France at a terrifying speed.
37:48After enveloping the vehicles trapped behind the burning truck, the smoke accelerates,
37:53now moving at 20 feet per second.
37:57On the French side, the whole French half of the tunnel was filled with smoke in little
38:02over half an hour.
38:09Catching the fire from either end of the tunnel is impossible, and all rescue attempts are
38:15called off.
38:25But a startling discovery is about to be made.
38:32Stay tuned, the conclusion in a moment.
38:37And now the conclusion of Seconds from Disaster.
38:43A fire in the Mont Blanc tunnel between France and Italy becomes one of the worst tunnel
38:48fires on record.
38:50A critical chain of events causes the disaster.
38:57And now investigators discover the final link.
39:02Throughout the entire rescue, none of the emergency teams or tunnel operators is aware
39:07of the 38 trapped motorists.
39:10The closed-circuit TV cameras are so quickly blocked by the smoke that it's impossible
39:15for the tunnel operators to see them.
39:19Emergency telephones only work intermittently, and sensors that detect smoke aren't adequate.
39:25In fact, one is even turned off the day before the fire.
39:30Worse still, there is no communication between the French and Italian rescuers.
39:35Italian firefighters become trapped.
39:38It is a totally uncoordinated effort.
39:41Tackling a fire of this severity seems to take everyone by surprise.
39:46A lack of fire drills might explain why it's more than three hours after the fire begins
39:51that the last of the trapped Italian firefighters are brought out through the underground ventilation
39:56ducts.
39:57They were absolutely black.
40:01You couldn't see the color of the helmets or the uniforms.
40:04You couldn't see the color of the fire engines.
40:07Everything that came out of that tunnel was black.
40:11It was a horrible, horrible sight, really.
40:15The inferno rages for 53 hours before it's extinguished.
40:27I really hope that something is done to improve the safety of these tunnels.
40:34The disaster triggered an overhaul of safety procedures in the Mont Blanc tunnel.
40:40Today, maximum speed limits and minimum distances between vehicles are strictly enforced.
40:50Seventeen previous fires in the tunnel were caused by trucks, but now sophisticated thermal
40:55sensors at each entrance scan all trucks to detect dangerous heat emissions before
41:01they enter the tunnel.
41:08The tunnel operators have gone a long way to correct the mistakes.
41:14They stage regular fire and evacuation drills.
41:23The shelters are now pressurized and equipped with a video link to the control room.
41:35Staircases now connect them directly to evacuation tunnels below the road.
41:45There is now a firefighting team permanently based in the center of the tunnel.
41:52And fire trucks are equipped with heat-seeking systems so they can locate people in zero
41:58visibility.
42:04March 24, 1999 provided clues that may save lives in the future, but it's small consolation
42:10for relatives of the people who died in the tunnel, including one firefighter who died
42:16from his injuries later.
42:22Xavier Chantelot will never be the same.
42:29I lost my mother-in-law, her daughter, my wife's sister, and also her fiancée.
42:37They'd all been staying with us on holiday.
42:42For relatives of the victims, like Xavier, there are still many unanswered questions
42:47regarding the final moments of loved ones lost inside the tunnel.
42:55We still do not know for sure how they died.
42:58I'm sure I don't need to describe the horrific images I have in my head.
43:03People running about on fire or collapsing, trying to get out.
43:08You think of everything.
43:12The Mont Blanc Tunnel fire and its critical chain of events reveals the dangers of deep
43:17road tunnels.
43:21On that day, a large white truck enters the tunnel.
43:26A small fire under the cab gives off a stream of white smoke.
43:31The truck stops.
43:33More air reaches the fire, causing it to erupt.
43:40The ordinary cargo of margarine turns deadly, creating a fire with the same potential as
43:46an 8,000-gallon fuel taker.
43:55Unusual weather conditions and incorrect use of the tunnel's ventilation system creates
44:00a wall of smoke that quickly envelops 38 trapped motorists.
44:05They have no chance of survival.
44:08But was this critical chain of events unique?
44:15I think there will be another fire in the Mont Blanc Tunnel tomorrow, in six months,
44:21a year.
44:22But the emergency services are better adapted today than they were at the time of the disaster.
44:29But there will be another fire.
44:36Is another Mont Blanc disaster possible somewhere in the world?
44:39Yes, it is.
44:41And it's perhaps only a matter of time.
44:47But until it happens, millions of vehicles will continue to travel through road tunnels
44:53every day.
45:06This is the National Geographic Channel.