A tanker carrying acetic acid overturned on the Mumbai-Goa national highway.
Three bystanders were injured as they were hit by stones which flew off as the tanker turned turtle on the roadside at around 9.45 am at Dasgaon village near Mahad in Raigad district, highway police said.
The tanker was heading for a textile company in Mahad from Chembur in Mumbai, police added.
The accident caused a traffic jam on the busy road.
Police also stopped the traffic for half an hour for cleaning up the chemical which leaked from the tanker.
Apart from highway police and fire brigade personnels, experts from MIDC (Maharashtra Industrial Development Corporation) also visited the spot to check the severity of the chemical.
Traffic smoothened after noon.
Injured persons were admitted to a hospital in Mahad.