That is what safe looks like, nobody said perfect. It's like how cars are death traps but people can still reasonably call them "safe". You could do the same thing for solar panels but for the fact it isn't newsworthy if there is some toxic sludge in some dump somewhere is associated with solar panels.
There might not be any material that we produce on an industrial scale that doesn't leak hazardous or toxic chemicals. I looked up concrete [0] to find out what it's problem was, and it turns out concrete leaks toxic and radioactive materials into the environment because turns out natural rock is sometimes radioactive. Concrete is nonetheless pretty safe stuff.
[0] https://en.wikipedia.org/wiki/Environmental_impact_of_concre...