Something foreign fit on this weekend at a manufacture plant in Salem , Massachusetts . After dozens of workers appeared to hang acutely sick , it was suspected that a mysterious chemical leak was the cause . However , authorities have since speculated that they may   have been battling with a more peculiar billet : a “ mass delirium ” consequence .

It all began on Sunday afternoon when fireman were phone to the Thermal Circuits industrial plant to investigate a chlorine making water , CBS Bostonreports . A crew don hazmat suits entered the building and promptly purpose the problem . No one was injured and the atomic number 17 level returned to normal .

All appear to be well until the emergency services were called once again later that evening . rafts of prole had fly out of the plant complaining of breathing problems , sickness , and hard vertigo . In total , around 30   workers were hospitalized and one someone even appeared to meet a gaining control .

However , firefighters said they did n’t find any chlorine in the construction during their second visit .

In a instruction received byBoston 25 News , the Salem Fire Department said the emergency service " find no contaminant that would be wild . "

" New carpeting was being instal in the building that did leave odors , but no hazardous or dangerous reading were detected . "

So , what the hell live on ?

Fire Chief Alan Dionne toldCBS Bostonthat the event was " aggregated craze " and distinguish " a panic in the building . "

Mass hysteria , or collective hysteria , is a phenomenon that ’s been document throughout story . research worker do n’t in full understand the psychological in - and - out of it , but it typically describes theen massespontaneous development of identical forcible or emotional symptoms among a group of hoi polloi .

One of the most notable instance of collective craze is the 1983 West Bank fainting epidemic . Nearly 1,000 people , virtually all of them teenage Palestinian girls living in   the West Bank , were hospitalized between March and April 1983 after falling acutely sick and fainting . Due to the het up political clime in the area , many suspected a malicious   " environmental irritant ” . Yet no poisonous substance were discover .

A reportby the US Centers for Disease Control and Prevention ( CDC ) indicate that some of the miss might have been poisoned by a hydrogen sulphide gas ;   however , the immense majority of typeface were just young women with psychogenic illness , perhaps exacerbated by the high levels of stress associated with living in the West Bank country in the 1980s .

It might seem unconvincing , but corporate hysteria can provoke   a powerful reply . Until prescribed investigations   are finished up , it ’s too early to conclude that this is what go down in Salem this hebdomad .   A spokesman said the plant would " absolutely not " be reopening on Monday .