I am trying to remember a Hawaii Five 0 episode.. It was about a toxin in a vial which was left in a shallow stream . Jack Lord and company were trying to find it. Regularly, as time ran out, the camera would cut to a shot of the vial in the water.

It is not Three Dead Cows at Makapuu or Nine Dragons both of which have a toxin theme. I am almost sure it was a Five-0 episode. If anyone knows I would appreciate it. I have searched several time