A group of school children in Ohio volunteered to be pepper sprayed in the face by a police officer as part of a criminal science technology class.

Shocking footage shows students from Barberton High School in Ohio standing in line and getting sprayed in the face by an officer after telling them "stop resisting, please comply".

The teenagers are then heard screaming and writhing in agony as the effect of the burning mace take hold.

Before getting sprayed, the volunteers needed to get a waiver signed by their parents to give them permission to the sprayed by the OC.

The letter, from the chief of Barberton police, reads: "Dear Parent(s) or Guardian, On Friday, May 12, 2017, as part of our defensive tactics training that we have covered this year, I will introduce the use and effects of law enforcement OC 'Pepper Spray' to the students.

"Each student will have the option to be swabbed or receive a quick 'burst' to the facial area with this chemical agent. It will cause irritation and a burning sensation to the eyes and nasal area for approximately 30 minutes to 1 hour.

"This is a controlled and safe experience for the students and is completely voluntary."

The video was posted on the pro police Blue Lives Matters website and has since been viewed more hundreds of thousands of times.

A statement on the website said: "You may wonder why anybody would volunteer to go through such an experience, and there's only one answer: ignorance. Anybody who actually knows what the OC spray entails is likely to pass on the experience."

pepper spray