There is possibly no greater icon representative of the struggle of the human population than that of the gas mask. One does not have to look too far into history to see the effects that the issuance of gas masks had on the general population up and until the nuclear age, which usurped the chemical threats of the industrial revolution.
As an icon, the gas mask would be expected to have outweighed -on some levels- that of the hazard materials suit, (which is representative of course of nuclear fallout); however, for some reason the hazmat suit is lacking in the production of sheer terror that the gas mask is still historically able to elicit. Consider if you would this article from Military Science magazine published in January 29, 1938:
"EUROPEAN nations are piling up stocks of gas masks for civilians and spending huge sums in the construction of gas proof shelters, reports Lt.-Col. Augustin M. Prentiss of the U. S. Army chemical warfare service. England is engaged in manufacturing 30,000,000 gas masks, in an effort to provide protection for every person in the kingdom. France already has accumulated 8,ooo,ooo for its active civilians, Germany has on hand 7,5oo,ooo, and Italy 5,000,000 for the same purpose. Cost of gas shelters ranges from $I50 for a single room to $Ioo,ooo for large communal shelters capable of accommodating several thousand persons. In France, plans have been drawn for the construction of fifty large gas shelters in the subways, at an estimated cost of $s,ooo,ooo. Germany believes in a decentralized gas defense system, and it is claimed that more than half a million such small shelters have already been built. Similar construction is also under way in Japan. According to Lt.-Col. Prentiss, civilians are classified into "active" and "passive" groups. The former, about ten per cent. of the total population, comprise police- men, firemen, decontamination squads, and others who must stay out even in the thickest of the gas attack to preserve order and clear out the gas after the raiders have flown away. The great "passive" bulk of the people can best meet a gas raid by taking shelter until it is over. For the active civilians, elaborate gas- proof suits have been designed, together with military-type masks giving full protection. For the passive group, less elaborate and costly equipment, effective during short exposures only while they make for the gas proof shelters, is considered sufficient." (The Science News-Letter, Vol. 33, No. 5 (Jan. 29, 1938), pp. 76-77)
In retrospect it is easy to see that the chaos of the era of World Wars I and II left the world population scared. The industrial era had brought about weapons of mass destruction which were second to none historically and which were immediately capable of rendering the majority of the world's population either dead or disabled. Finally the world had evolved to the point that it could easily orchestrate it's own destruction. It very nearly did, and the gas mask stands now as an eternal reminder of the fact that there is always someone out there who would like to kill you, and there is always a means by which to do it.