Ammonia was squirted at a car driver and his passenger in a robbery after the driver refused to hand over his keys.
Two men wearing balaclavas approached the driver in Boleyn Road, Forest Gate, as he was loading it with some building materials on July 27 at about 11.30pm.
They demanded his car keys and when the man refused to do so, he was assaulted and sustained an injury to his leg.
Both men were then targeted with the ammonia before the robbers fled the scene empty-handed.
Paramedics later took both individuals to hospital. Their injuries are not believed to be serious.
Detectives are investigating. No arrests have been made and enquiries continue.
Anyone with information is asked to contact police on 101 or directly on 07747 780610.
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