Gas attacks at Hulluch

The gas attacks at Hulluch were two German cloud gas attacks on British troops during the First World War, from 27 to 29 April 1916, near the village of Hulluch, 1 mi (1.6 km) north of Loos in northern France. The gas attacks were part of an engagement between divisions of the II Royal Bavarian Corps and divisions of the British I Corps.

Just before dawn on 27 April, the 16th (Irish) Division and part of the 15th (Scottish) Division were subjected to a cloud gas attack near Hulluch. The gas cloud and artillery bombardment were followed by raiding parties, which made temporary lodgements in the British lines. Two days later the Germans began another gas attack but the wind turned and blew the gas back over the German lines. A large number of German casualties were caused by the change in the wind direction and the decision to go ahead despite protests by local officers. German casualties were increased by the British, who fired on German soldiers as they fled in the open.

The gas used by the German troops at Hulluch was a mixture of chlorine and phosgene, which had first been used on 19 December 1915 at Wieltje, near Ypres. The German gas was of sufficient concentration to penetrate the British PH gas helmets and the 16th (Irish) Division was unjustly blamed for poor gas discipline. It was put out that the gas helmets of the division were of inferior manufacture, to allay doubts as to the effectiveness of the helmet. Production of the Small Box Respirator, which had worked well during the attack, was accelerated.

By the end of the Battle of Loos in 1915, the British armies in France held ground which was usually inferior to the German positions opposite, which were on higher ground, which was drier and had good observation over the British lines and rear areas. In early 1916 the British took over more of the Western Front, to allow the French Tenth Army to move south to Verdun, ground which was just as tactically disadvantageous. Only around Armentières were the German defences on lower ground. The possibility of a withdrawal to more easily defensible ground was rejected by Joffre, the French Generalissimo and all the Allied commanders preferred to improve their positions by advancing. With this in mind, the French and British made far less effort to improve their defences, which conceded another advantage to the Germans, who could attack positions protected by far less extensive barbed wire barriers and few deep-mined dugouts than their own. Allowing such positions to relapse into quiet fronts was rejected by the British, who instituted sniping, unpredictable artillery bombardments and raids, which provoked German retaliation; the British conducted three attacks against five by the Germans and numerous raids.

In early 1916, the Germans had more and better equipment for trench warfare, with good quality hand grenades, rifle grenades and trench mortars; the Germans made more effort to repair and improve defences and with a homogeneous army, found it easier to move artillery, ammunition and men along the front. A substantial cadre of the pre-war trained officers and conscripts remained, to lead the wartime recruits. British tunnellers achieved an ascendancy over their German equivalents but in ground operations, the number of operational machine-guns and the volume and accuracy of artillery-fire had more effect than individual skill and bravery; the quantity of heavy guns often determined the course of engagements. The success of a local attack left the victors vulnerable to a counter-attack and captured positions were often more costly to hold than the previous positions.

The German began preparing for the attack during April, placing about 7,400 gas cylinders along a 3 km (1.9 mi) front from Cité St Elie to Loos, where no man's land had been only 120–300 yd (110–270 m) apart since the Battle of Loos (25 September – 14 October 1915). German artillery began a systematic bombardment of British observation posts, supply points and communication trenches, supplemented by trench mortar and rifle grenade fire. Shelling diminished from 24 to 25 April and on 26 April, the positions of the 16th (Irish) Division were bombarded and the 12th (Eastern) Division front was raided. The next day was fine and warm, with a wind blowing towards the British lines. The 4th Bavarian Division was to follow up a gas attack on 27 April with patrols against the British positions. Two days later, despite less favourable winds, a second gas discharge was ordered against the wishes of the local commanders, who were over-ruled.

A German soldier deserted on the night of 23/24 April and warned the British that an attack on the Hulluch front, probably with gas, was imminent, which confirmed indications already noticed by the British. Rats had been seen moving away from the German trenches and was inferred to be due to leaky gas cylinders. The systematic bombardment of British defensive positions and the testimony of the deserter led Lieutenant-General Charles Kavanagh, the commander of I Corps, to issue a warning to the 1st Division which held the line from Lens to Loos, the 16th (Irish) Division in the centre from Puits 14 bis to Hulluch and the 12th (Eastern) Division to the north, opposite The Quarries and the Hohenzollern Redoubt. The 15th (Scottish) Division relief of the 12th (Eastern) Division from 24 to 30 April was allowed to proceed. Four reserve artillery batteries were moved into the 15th (Scottish) Division area and all units were required to rehearse gas alerts daily. The British were equipped with PH helmets, which protected against phosgene up to a concentration of 1,000 p.p.m.

The German attack near Hulluch began with the release of smoke, followed by a mixture of chlorine and phosgene gas 1½ hours later, from 3,800 cylinders, on the fronts of Bavarian Infantry Regiment 5 (BIR 5) and Bavarian Reserve Infantry Regiment 5 (BRIR 5). The discharge on the front of Bavarian Infantry Regiment 9 (BIR 9) was cancelled, as the direction of the wind risked enveloping the 3rd Bavarian Division on the right flank, in the Hohenzollern Redoubt sector. At 5:00 a.m., German artillery began a high-explosive, shrapnel and trench-mortar bombardment, on the front of the 16th (Irish) Division and the right flank of the 15th (Scottish) Division to the north, laid a barrage on communication trenches and fired lachrymatory shells into villages and British rear positions. At 5:10 a.m., gas and smoke clouds rose from the German trenches and moved towards the British trenches, blown by a south-easterly wind. The gas cloud was so thick at the beginning, that visibility was reduced to 2–3 yd (1.8–2.7 m); wearing gas helmets was necessary 3.5 mi (5.6 km) behind the front line and the smell was noticed 15 mi (24 km) away.