Two persons — a student and watchman — have died in a freak accident in a laboratory of a private polytechnic institute near Udumalpet in Tirupur district, when a car engine exploded on Wednesday. Four students suffered grievous injuries and have been rushed to a hospital in Coimbatore.

According to the police, lecturer S Sahul Hameed (28) of Rudraveni Muthusamy Polytechnic college was explaining the functioning of a petrol car engine to 24 second-year students of mechanical engineering. When students started the car engine, it picked up momentum. Suddenly, the fly wheel broke and hit the head of a student, P Chevvel Kumar (18) who died on the spot. P Chelladurai (52), watchman, who brought petrol for the engine, was also killed on the spot.

E Kavimani (19), S Sivaraman (18), Sahul Hameed and college bus driver B Senthil Kumar (43) were severely injured.

Over 300 students contducted a road-roko near Udumalpet bus stand against the college management.

"We have lodged a complaint against the college management under Sections 287 (negligent conduct with respect to machinery), 337 (causing hurt by act endangering life or personal safety of others) and 304 (a) (causing death by negligence) of the IPC" said Udumalpet inspector K Rameshkumar.