In the middle of the 1930s, Britain released its first formal statement about air raid precautions (civil defense) and acknowledged that it could offer no guarantee of immunity for civilians in a future war that might involve both air power and chemical weapons. At the start of the decade, Britain had begun to create civil defense for chemical warfare by cultivating first aid for civilians facing chemical arms and continuing to test both chemical weapons and anti-gas protection. It had not yet decided whether to provide gas masks to its entire civilian population. The official release of civil defense measures in 1935 led to vocal opposition from a variety of groups including feminists, socialists, scientists, and religious pacifists like Quakers. Then, the return of the use of chemical weapons in the Second Italo-Ethiopian War of 1935–36 dramatically altered the public conversation about the use of such weapons and the devices to protect against them. The return of aerial bombardment to Europe with the Spanish Civil War alongside the use of chemical arms served as a catalyst for developing anti-gas protection as a key component of civil defense preparations for the war to come.