A manhunt has been launched after a masked man 'released gas' on the Manchester Metrolink which left passengers 'feeling dizzy' and 'losing consciousness'.
The alleged gas attacks took place on two separate occasions on the Bury line of the tram network and left commuters worried what they might have inhaled.
The first incident took place on Thursday March 20 and then again on Saturday March 22.
According to the Manchester Evening News, the suspect, who boarded between the Queen's Road and Crumpsall area, was spotted wearing a gas mask covering his mouth moments before commuters heard a 'hissing' sound and were hit with the strong smell of gas.
It is thought the substance was butane gas.
One passenger, who witnessed the incident on Thursday said: 'I was sat on the tram and a guy got on at Queen's Road wearing a blue face mask with an industrial gas mask over the top of that.
'There was a hissing noise and people started looking around. And then we smelt gas, it was really strong. One girl who was near him got up and moved away from him. People looked really concerned.
'I had a headache and felt dizzy and a bit sick. When the tram got to Abraham Moss, myself and a few other people got off and I reported it to the police.'
The alleged gas attacks took place on two separate occasions on the Bury line of the tram network
There were numerous reports about another incident on board the same Bury line service on Saturday.
'Some fella was on the tram with a gas mask letting off some gas and everyone had to get off,' one person wrote online.
Another added: 'I was on it, was sat across from him and watched him twist the gas canister in his pocket to let it out.'
A person on Facebook said: 'Last night on my way home from work on the Metrolink from Market Street to Bury, a man got on the back of the crowded tram wearing an industrial grade gas mask wearing a blue hoodie and a backpack.
'After two minutes of him getting in he started too fidget in his pocket, everyone started to worry and panic, lots of people started to run down the tram away from him, the smell and the effect of whatever substance he released was extremely strong I nearly lost consciousness after five seconds.
'I called all the emergency services and was quarantined and detained for four hours in the back of a van. Thankfully I'm alright and everyone else effected seemed ok. God knows what we have breathed and I can only thank god for whoever is watching over me as it could of been a lot worse.'
MailOnline have approached Greater Manchester Police and Transport for Greater Manchester have been for comment.