Police 'jet pack' solution more powerful than pepper spray or tear gas, says Post photographer hit by all three

A pepper spray-based solution used by police on pro-democracy protesters was "much more powerful" than pepper spray and tear gas, according to a South China Morning Post photographer temporarily blinded by it.

The first-hand testimony contradicts police descriptions of the solution's "mild" chemical effects, as the force remained coy about its new riot control agent.

"I lost my sight for 30 minutes and the solution just wouldn't go away. I even tried washing it out with water," said Sam Tsang Kwok-chung, who was hit by the substance as he covered the operation to clear protesters in Mong Kok on Tuesday.

Tsang said he had been hit by tear gas and pepper spray during his work covering the Occupy Central protests, but his goggles offered little protection against the solution.

He added that he was standing about 10 metres from the officer who sprayed him in the face.

"The effect of tear gas only lasts for two to three minutes, but there's nothing you can do with pepper spray solution except wait until it dies down," Tsang said.

"During those 30 minutes, I could only tell vaguely where the light source was and I had to rely on my sense of touch to tell what was around me."