British Transport Police are appealing for information after a bottle of hydrochloric acid was found on a Northern Rail train at Middlesbrough station shortly after 7 o'clock on Sunday evening.
The station was evacuated for a time and buses replaced train services.
4 fire appliances attended the incident along with 3 special appliances and 3 officers.It is believed the acid was in a soft drink bottle and caused the smell of burning when some of the liquid leaked from the container.
More top news
The North East has had the biggest fall in C/4 grades than any other English region, putting it significantly behind the national average.
4 in 10 adults aged 40-60 in the North East do not achieve ten minutes of continuous brisk walking over a month according to new figures.
A Darlington-built steam locomotive replica features in the latest Paddington film, which will be released later this year.