The St Marys fragmentation grenade explosion
The accidental explosion of a fragmentation grenade in a munitions factory at St Marys injured four workers, two critically. The prompt response by ambulances and physician-staffed helicopter emergency medical service prevented deaths, but the incident suggests lessons for the future handling of urban explosions. (MJA 1997; 166: 545-548)
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|On 14 November 1995 an F1 fragmentation hand
grenade exploded in a grenade testing facility in a munitions factory
on a 1600 hectare site at St Marys, NSW. Seven employees were in the room.
The grenade exploded at 8:36 am on a work bench and injured four workers
around the bench (Figure 1). None were wearing body armour and there were
no blast shields in the work area.
The first ambulances arrived at 8:41, 8:44 and 8:47. The four injured workers were extricated from the factory building to an adjacent courtyard by other employees and ambulance personnel. NRMA CareFlight, a Bell 412 HP helicopter emergency medical service (HEMS) with a physician on board, was placed on standby at 8:45 and dispatched at 8:50, landing at the site at 9:06.
Two patients were transported by air to a trauma centre with full cardiothoracic facilities about 24 km (10 minutes' flying time) from the factory. Access to this centre by road would have encountered peak hour traffic flowing into Sydney via the major western arterial road routes. Two patients were transported by road to a local trauma centre (10 minutes' travelling time) which has limited cardiothoracic surgical facilities.
|Patient A was a 44-year-old woman sitting 0.25 m from the grenade burst
point. On arrival of the HEMS, she had a Glasgow coma score of 12-13 and
no recordable blood pressure. Only carotid pulses were palpable after an
infusion of 1.5 L of polygeline by ambulance personnel; an additional 500
mL polygeline and 500 mL normal saline were infused. The patient's conscious
state began to fluctuate, and a rapid sequence induction and endotracheal
intubation were performed before transport by helicopter. The patient received
a further two units of O negative blood during transport.
On arrival at hospital, Patient A had a heart rate of 100/min, systolic blood pressure, 118 mmHg; haemoglobin level, 79 g/L (normal range, 115-165 g/L); pH, 7.29 (normal range, 7.35-7.45); PO2, 518 mmHg (normal range, 75-100 mmHg); PCO2, 30 mmHg (normal range, 35-45 mmHg); HCO3, 14 mmol/L (normal range, 22-26 mmol/L); and serum lactate, 3.04 mmol/L (normal range, 0.63-2.44 mmol/L). She was taken to theatre for thoracotomy and laparotomy, enucleation of left orbit, amputation of right ring and little fingers, debridement of right forearm and thigh, with internal fixation of her right forearm fractures. By the end of her first theatre session she had received (in addition to her prehospital fluids) 6.5 L of polygeline, 4 L of crystalloid, 24 units of packed red blood cells, 8 units of frozen plasma and 6 units of platelets.
Patient A's injuries were:
After her initial surgery, Patient A required mechanically assisted ventilation for 11 days and underwent five additional operative procedures during her initial 39 days in hospital. In the next year she underwent another five operative procedures, with a further five reconstructive procedures scheduled for the following year.
|Patient B was a 45-year-old woman standing behind and to the left of
Patient A, about 0.6 m from the grenade burst point. On arrival of the
HEMS, she was in severe respiratory distress, with a heart rate of 105/min,
systolic blood pressure of 60 mmHg, and Glasgow coma score of 10. Patient
B was treated by ambulance personnel with 1.7 L of polygeline and transported
to hospital by road.
On arrival at hospital, Patient B had a heart rate of 88/min; systolic blood pressure, 140 mmHg; Glasgow coma score, 15; haemoglobin level, 83 g/L; pH, 7.30; PO2, 331 mmHg; PCO2, 36.6 mmHg; HCO3, 17.8 mmol/L; and base excess, - 7.2 (normal range, - 3 to 3). Patient B was taken to theatre for laparotomy and cholecystectomy. Her injuries were:
|Patient C was a 54-year-old woman sitting to the right of patient A,
1.3 m from the burst point. On arrival of the HEMS, she had a heart rate
of 80/min, systolic blood pressure of 130 mmHg and Glasgow coma score of
14. She was treated with 1 L of Hartmann's solution and 250 mL of polygeline
and transported by air.
On arrival at hospital, Patient C's heart rate was 83/min; systolic blood pressure, 151 mmHg; Glasgow coma score, 14; and haemoglobin level, 125 g/L. Her injuries were:
|Patient D was a 50-year-old woman sitting diagonally opposite Patient
A about 1.6 m from the grenade burst point. On arrival of the HEMS, she
had a heart rate of 105/min, systolic blood pressure of 70 mmHg and Glasgow
coma score of 11. She was treated with 1 L of polygeline and transported
by road. On arrival at hospital, Patient D had a heart rate of 90/min;
systolic blood pressure, 150 mmHg; Glasgow coma score, 15; and haemoglobin
level, 108 g/L. Her injuries were:
|The injuries of the four accident victims demonstrate the capability
of military weapons to inflict serious physical injury -- but the potential
psychological impact of these weapons extends well beyond their injury
The grenade exploded on a bench top, which directed most of the blast and fragments onto the upper torso of the victims, but it also blew a hole in the bench top, producing the wound to the right thigh of patient A.
Any bomb or blast scene should always be considered dangerous until declared safe from the risk of secondary explosion by appropriate technical personnel. Specialist bomb disposal personnel were not part of the initial response to the St Marys incident, which contributed to the delayed recognition of a potential secondary explosion hazard from 48 damaged grenades at the site.
The size and shape of modern military weapons often belie their wounding potential. Explosive devices may contain fuse mechanisms that detonate in response to stimuli other than that of direct impact. The bodies of victims may conceivably hold unexploded devices that pose a threat to rescue, medical and mortuary personnel.11,12 Major injuries and deaths occurred during the Gulf War among medical and service personnel handling souvenired battlefield ordnance.13
Injury from military weapons is uncommon in Australia. Army ammunition technical officers can provide expert advice on the composition and function of a particular device. This information is vital in the assessment of individuals wearing body armour, or who have been potentially exposed to either radiolucent fragments or items of ordnance which have become airborne.11,12
Early on-site specialist technical advice is critical to safe operations at the scene of an urban explosion.
Helicopter emergency medical services have been used in the primary and secondary transport of blast victims.14,15 In this incident the HEMS rapidly provided a doctor on-site to assist in trauma triage. This allowed patients to be referred immediately for specialist surgical care, while dispersing casualties over a wider network of receiving hospitals (thus Patient A and Patient B were sent to different hospitals so that both could receive immediate surgical treatment; this would not have occurred under ambulance protocols). In addition, on-site medical care went beyond the scope of paramedic protocols16 (e.g., in performing a relaxant-assisted intubation and giving a blood transfusion).
The NSW Ambulance Service Disaster Plan (December 1995) precludes the immediate dispatch of physician-staffed helicopter emergency medical services to potential multicasualty incidents. This may introduce avoidable delays in delivering seriously injured patients to definitive surgical care, especially in incidents geographically removed from designated trauma centres.
|I thank Mr Mike Etzel for generously providing some of the background material.|
NRMA CareFlight, Westmead, NSW.
Antony Nocera, MB BS, Emergency Medicine Registrar.
No reprints will be available. Correspondence: Dr Antony
Nocera, NRMA CareFlight, PO Box 159, Westmead, NSW 2145.
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