When a serious accident involving a cannon occurred during a local Proms concert, Ryedale DC found their health and safety knowledge stretched beyond ordinary limits. Robin Rawson and Carol Rattenbury recount the learning curve which resulted in a successful prosecution

Environmental health officers can find themselves applying their expertise to some unusual situations, but a cannon explosion is extraordinary even by these standards, and an accident in Ryedale's district saw several disciplines involved in a steep learning curve.

Local authority enforcement applied, as the accident occurred during an outdoor event - but this was a major investigation for a department with only one health and safety specialist. The Napoleonic period could have furnished many experts in muzzle-loading cannon; not so the late 20th century. As a result, this complex case required widespread liaison; with the HSE (Local Authority Unit and Explosives Inspectorate), police (both in Suffolk and Yorkshire), the Gun Barrel Proofing House, the American Civil War Society, the Royal Armouries and the Sealed Knot Association.

The Concert
A "Last Night of the Proms" concert including displays of fireworks and cannon was organised by Window Through Time and held on Saturday 22 August 1998, at Castle Howard, North Yorkshire. Ryedale was responsible for licensing the event, which included briefing Castle Howard staff over arrangements and assessing the site for public safety.

The Accident
While the Midland Symphony Orchestra played Beethoven's Battle Symphony, live cannon fire was employed to heighten the experience. The special effects were created by several full-size cannon and banks of mortar tubes provided by the Trafalgar Gun Company, run by Martin Bibbings. A gun crew member was seriously injured when her cannon discharged prematurely. She sustained injuries to her right hand and wrist, losing two fingers (a third was surgically removed later), and the palm of her hand. The bones in her wrist and lower arm were smashed, her face was seriously burnt (black powder was embedded in the wounds); and the blast was also thought to have burnt her lungs.

THE INVESTIGATION
The investigation fell into three distinct areas:
1. the events of 22 August 1998
2. the procedures used leading to the accident
3. the accepted procedure for firing muzzle-loading weaponry.

The events
The witness statements and Section 20 interviews of the gun crews, and a PACE interview with Mr Bibbings, established the following sequence:
i. Mr Bibbings arrived at 10am to set up the guns and mortars with home-made black powder charges of aluminium held together with masking tape.
ii. The volunteers helped load the mortar tubes and wire them to electric detonators.
iii. During the concert the crews dressed in military-style costume and assumed their tableau positions.
iv. At a given signal the loaded guns were prepared for firing. Two of the volunteer gunners manned a grey 6lb field gun and a small green howitzer.
v. They fired two shots from the howitzer, and repeated the routine for the field gun.
vi. While preparing the second discharge, the powder ignited prematurely, propelling the ramrod out of the gunner's hand, causing severe injury.
firing the cannon

A crew of two was asked to fire two shots from both guns within a four-minute window during the music. One team member acted as gun captain while the other served as crew.
Both guns were already loaded, but only primed during the performance.
i. The gun captain spiked the charge and primed it with fine powder. On his own command, "Fire", the linstock was placed to the vent, firing the blank charge.
ii. On the captain's command, the barrel was immediately cleaned with a damp swab.
iii. The crew took a new charge from the secure store behind the gun, and rammed it down the barrel, followed by wadding.
iv. The cartridge was spiked, primed and fired.
v. The crew turned to the second loaded gun, primed and fired.
vi. The barrel was swabbed.
vii. The second charge was brought up and loaded. As it was rammed home, the charge detonated discharging the ramrod.

Both the discharge of the tool and the blast caused injury. The crews followed the techniques they had been taught to use, and were familiar with using. We needed more information to thoroughly understand the case. Croner's Health and Safety at Work Issue 154 discusses the status of volunteers, and was very helpful in establishing responsibility for the accident.
Questions regarding the safety of the equipment were raised. We commissioned reports from the Birmingham Gun Barrel Proof House and the HSE Explosives Inspectorate. These concerned the suitability and condition of the gun; and the handling of explosives, including the assembly and use of black powder cartridges.

We also researched the construction and safety of tools provided for the gun crews, the training they required to work safely, and the training they actually received. We questioned whether the specific properties of the black powder used made it more prone to premature detonation. In fact Colonel Farquharson's Favourite Sporting Black Powder has very low sensitivity to ignition by friction or impact and is thermally stable, though it is highly sensitive to ignition by electric spark or flame. Aluminium melts at 660oC and boils at 2467oC. The detonation temperature would not exceed 2200oC. Consequently the foil cartridge could burn but not vaporise. As oxygen re-enters the barrel the residue oxidises to fine white powder capable of igniting any remaining tape from the cartridge.

Procedural Safety
The volunteers assumed the procedures they followed were safe, yet a discrepancy between experts in period weaponry and Mr Bibbings soon appeared. While different organisations do have slight procedural variations, the routines they cite for safe loading and reloading all include worming. Worming is a process in which a wooden shaft, with a metal helical head (the worm) is inserted into the barrel and twisted, to ensure the gun is free of extraneous material. The overwhelming weight of expert opinion saw this as vital prior to wet swabbing when using aluminium foil cartridges (which may make a waterproof shield).

Mr Bibbings wormed his guns before the event, but did not consider worming between shots necessary. He insisted that worming was only to prevent accumulated cartridge bases blocking the vent, not a safety procedure. His reasoning that everything would be vaporised and that aluminium does not burn contradicts the known properties of aluminium.

Training deficiencies
The crews received some training in gun drill, including the need for safety, and took the precaution of not firing adjacent guns. They understood the need to seal the touch-hole during swabbing to create an oxygen-depleted vacuum. The injured person acknowledges that when swabbing the second gun, the tool turned and withdrew easily. At the time she attributed this to improved strength and skill, not failure to achieve a vacuum. While knowing the need for a vacuum, the gunners weren't equipped to identify the danger. Volunteers operating the other guns on the night insist they were allowed to fire cannon after only observing a single event, and that one acted as gun captain during his first season with the Trafalgar Gun Company. This contradicts Mr Bibbings' insistence that only well-trained and experienced volunteers operated his guns.

Assessment deficiencies
Throughout the investigation Mr Bibbings claimed to be the country's foremost expert in handling muzzle-loading weaponry, citing consultations for television period dramas. He asserted a total safety culture, but demonstrated little awareness of the law pertaining to explosives, eg driver training or the licences his volunteers should possess. Interviews with members of the HSE's Explosives Inspectorate of the Chemicals and Hazardous Installations Division confirmed this:
"He did not assess the suitability of aluminium foil for black powder cartridges, or the placing of masking tape on the cartridge. When setting up his business Mr Bibbings enquired what to use, and was recommended foil, but evidently remained unaware of the additional precautions needed. This is probably because those giving advice assumed worming would be routine."
The cartridges' base should not be taped, to prevent residues adhering to the breech.
The size of the cartridges made up for the display demonstrated more concern for visual impact than crew safety. Though the guns can carry larger charges, the American Civil War Society and the Sealed Knot set a 4oz limit (this would carry a 4lb cannon ball two miles in 30 seconds). The charge that caused the injuries weighed 12oz. Such large charges were needless as the mortar tubes provided most of the noise and smoke. Smaller charges would not have lessened the audience's experience, but this was not considered.

Equipment Safety
The report submitted by the Gun Barrel Proofing House indicated that the weapon was safe to use, but its large calibre exempted it from proofing. A system that excludes worming must rely on efficient swabbing. Each gun was supplied with a wet swab and a ramrod. To extinguish heat and sparks in a gun barrel, the swab needed to be sufficiently wet, with maximum surface area exposure to the bore. The absorbent material needed to fit tightly in the barrel, requiring ramrods and swabs to be gun-specific. Photographs of a swab provided for another gun, showed the material taped in place, obscuring much of the surface area. Witnesses recalled that the swab provided for the 6lb gun was also taped. The significance of the swab made its recovery important. However, the rod was last seen heading towards the lake in the direction in which the guns had been deployed for crowd safety reasons. Police divers failed to find it, leaving the case for poor maintenance resting on the witnesses.

Manning levels
Normally four people plus a gun captain work an individual artillery piece. The captain gives the orders, and the others perform only one function. The accident involved only two. As the gun captain was part of the firing team, no-one had overall supervision. Mr Bibbings strongly disagreed that more people were required to operate the cannon safely.

Legal requirements
Mr Bibbings had an Acquire and Keep certificate permitting him to buy and store limited amounts of black powder. However, all those handling back powder also needed Acquire certificates, and those actually firing muzzle-loading weapons required shotgun or firearms certificates.

Human error
Failing to identify the absence of a vacuum while swabbing contributed to the accident, but this should not have been the only means of achieving safety. Was there an element of competition between the crews that could have overridden signals that all was not right? Everyone acknowledged the excitement of the experience, but no one raced to be the first to finish firing. While Mr Bibbings denies pressurising the crews to fire all four shots, professional pride may have driven the crews to comply with his request, possibly introducing a competitive element.

In the light of the evidence, it was considered that Mr Bibbings had failed to discharge the duties placed on him under Section 3 (2) of the Health and Safety at Work Act 1974, in that on the evening of 22 August 1998 at Castle Howard, York, he caused severe injuries to be sustained to one of the volunteers, exposed to risks to their health and safety people to whom he owed a statutory duty of care by failing to provide:
a) a safe system of work, and
b) adequate training and instruction.
Also, under the Management of Health and Safety at Work Regulations 1992 Regulation 3(b), he failed to carry out a suitable and sufficient risk assessment of the activities associated with the operation of Trafalgar Gun Company.

THE PROSECUTION
Mr Bibbings was found guilty of all three charges. The significance of the decision lies in according volunteers the same status under Health and Safety legislation as employees. It vindicates the safety procedures of re-enactment societies. It is also one of the few successful prosecutions for failure to undertake suitable and sufficient risk assessment under the Management of Health and Safety at Work Regulations 1992 Regulation 3(b).

CONCLUSIONS
When inspecting a re-enactment society demonstration or a performance involving live cannon fire it is important to:
i. be briefed on an obscure area of environmental health
ii. examine all the appropriate documentation
iii. verify that gun crews understand the procedures they are expected to follow and why.

Risk assessments should include:
i. methods that ensure the safety of the gunners, audience, and anyone else involved
ii. the safety of black powder, both storage and transportation
iii. detailed procedures of firing routines
iv. minimum crew sizes
v. the procedure in the event of failure to discharge
vi. evidence of barrel proofing even if greater than 2" bore
vii. evidence of the appropriate licences, or certificates
viii. training and years of experience.

This investigation required teamwork to assimilate information beyond our previous experience. Liaison with a wider body of experts demonstrates the need for co-operation beyond the confines of a small department. We believe the HSE publication Guidance to Re-enactment Societies requires prompt revision. It offers no advice to those using cartridges, and could even be construed as advocating the use of loose powder. As most societies use cartridges, guidance on their safe use should be included.