Human skin, hair and iron filings - the cocktail of what you are breathing in on the tube.
There were other passengers in the carriage at the time. Police want to trace the man seen in this e-fit.
Parts of the Tube have turned into an American-style metro on one of the world's most popular digital maps.
The figures also reveal also reveal which stations thieves are most likely to target with tourist hotspots coming top of the list.
Most thefts last year were recorded at Kings Cross St Pancras (283), with thousands of people using the station every day for journeys to Europe on the Eurostar and to Kent on the High Speed 1.
The second highest number of thefts was reported at Victoria (268), followed by Oxford Circus (255).
Londoners are more likely to fall victim to theft on the Circle and Hammersmith & City lines than any other London Underground route, according to new research.
Official figures from British Transport Police show that when crime figures are weighted against the number of passengers travelling on each line, the most thefts per person are carried out on the Circle and Hammersmith & City lines, followed by the Central line and Jubilee line.
Tube commuters at Paddington are to be banned from getting on Bakerloo Line trains for more than a month from next week.
Two escalators which carry 88,000 passengers a day are being taken out of service for essential repairs. Paddington Bakerloo Line station will be "exit only" from June 29th to August 22nd. 22,000 rail passengers from Paddington's mainline trains catch Bakerloo Line tubes during the rush hour.
– British Transport Police
It looks like a battery in a passenger's device which he had in his bag has overheated, and that is what caused the sparks and smoke to come from his bag.
We don't know what the device is, if it is a laptop or a computer.
He then approached staff and explained what happened. Our officers are on their way to Chancery Lane station to speak to staff and get his details.
We are not treating it as a suspicious incident, and nobody was hurt.
@bbcbreaking Tube: Smoke and sparks coming from cannister in carriage at Chancery Lane. Crying girlfriend thought she would die.
Stuck at Chancery lane, smoke everywhere something went off in a mans bag on the tube. Everyone screaming and running. Horrible experience ?
Unpleasant start to the morning at Chancery Lane station this morning as everyone ran off the train screaming about smoke leaking from a bag
Commuters fled a busy Tube station in panic today after a passenger's electrical device overheated, causing sparks and smoke to pour out of his bag. Passengers screamed and ran out of Chancery Lane station in central London while others were in tears following the security scare at 9.30am.
A British Transport Police spokesman said the man who owned the device immediately got off the Tube and spoke to staff after he realised his device was smoking. They said no one was hurt in the incident, and it is not being treated as suspicious.
No service between Waterloo and Wembley Park while we deal with a person on the track. Severe delays on the rest of the line.
Service has resumed with severe delays across the line, while the service recovers from an earlier customer incident.
– Mike Brown, Managing Director of London Underground
It is amazing that the Underground is carrying a third more customers now than it did only ten years ago, and customer demand shows no signs of letting up.
We know that London will see a rise in its population of more than a million people by 2031 - that's the equivalent to a city the size of Birmingham.