On the evening of saturday 18/06/11, I, along with friends, were walking south along Tongariro St, just before the traffic lights, when one of the females in our group slipped backwood on one of the two chamber covers due to the cover being so very slippery. I too nearly toppled when I slipped on the lid as a tried to save her fall. She is ok but has a bruised back today,19/06/11. I scuffed my foot over the other chamber lid to see if that too was as slippery to find it was as bad. Although our woman friend is ok, the result of the fall could have been worse for her, and worries me to think if an elderly person was to slip on one of these covers.