Some Roman writers, like the engineer Vitruvius, did note that lead workers seemed to suffer health problems and suggested clay pipes as a safer alternative. But lead was cheap, easy to shape, and extremely durable compared to the alternatives available, and the health effects of chronic low-level lead exposure (as opposed to acute poisoning) weren't well understood or consistently linked to the pipes themselves. Water also flowed through Roman pipes quickly and was often mineral-coated, which likely limited how much lead actually leached in — historians now debate how significant the real-world exposure was.