Two police officers were taken to hospital after being “exposed to a substance believed to be alkaline” during an incident at Surbiton station.
Two boys, aged 14 and 16, have been arrested on suspicion of possession of a corrosive substance in a public space and conspiracy to commit grievous bodily harm.
The teenagers were detained at around 4.20pm after British Transport Police (BTP) “spotted two people acting suspiciously” at Surbiton railway station in southwest London.
“As officers engaged with the people, they were exposed to a substance believed to be alkaline,” the force said.
Two officers were taken to hospital with injuries that are not believed to be life-changing or life-threatening, police said.
“Seven other officers, including two officers from the Metropolitan Police, were checked at the scene by paramedics,” a BTP spokesperson added.
“The 16-year-old has been taken to hospital as a precaution. Officers are not looking for anyone else in connection and enquiries are ongoing.
“The station was closed while the London Fire Brigade made the area safe, but has since been reopened.”
South Western Railway trains did not stop at the station for several hours during the closure while police dealt with the aftermath, causing significant disruption during the evening rush hour.
Services were running normally again by 7pm, the company said.