Environmentalist: Discarding old appliances can be dangerous: refrigerators contain chlorofluorocarbons; electronic circuit boards and cathode-ray tubes often contain heavy metals like lead; and old fluorescent bulbs contain mercury, another heavy metal.
Statements
Causal (doing X can be dangerous) Discarding old appliances can be dangerous, because they contain stuff like CFCs, lead, mercury.
Conditional (when) landfill operated → that stuff poses no threat properly
Pivot (however) Conditional (when) landfill not operated → lead / mercury properly contaminate groundwater
trash is incinerated → heavy metals poison ash and escape into air
Evaluate
Our job on Most Supported is to look for claims that can be combined.
When we see conditionals, we ask whether we can chain them together or apply them to a specific fact. But these two conditionals don't chain, and there's no specific fact to apply them to.
When we see causal claims, we ask whether we can chain them together, but these causal claims don't chain. It's not like we're hearing .
And when we see a Pivot, we ask ourselves whether there is some tension created that we could potentially explain (like on a Paradox question) or reconcile (by safely stating that both can be true).
But none of these typical games seem at play here.
It seems more like we have a potential Problem (discarding old appliances) and we're talking about different ways people handle that. From all we've heard, a properly operated landfill sounds like the way to go.
Improperly operated landfills can leads to groundwater contamination.
Incinerating the appliances can lead to poisonous ash.
Goal
With no clear guess in mind, let's just look for the most supportable claim, being wary as always of stuff that sounds too strong or that brings in concepts we didn't discuss.