LSAT Question Explanation
PT 105, Section 4, Question 9
WeakenArgument structure
The public shouldn't be concerned about the leak.
The law says that every new chemical must be tested for safety. The representative claims this is analogous to testing every pharmaceutical sucstance for safety.
Explanation
This is a flawed argument. First of all, it's not a convincing analogy because there may be different standards by which pharmaceuticals and the chemicals in the dump are tested. Pharmaceuticals are generally consumed or put into people's bodies so I would imagine there could be stricter standards than for some other chemicals. It's possible that the chemicals in the dump could be highly toxic (maybe only fit to be used in a regulated/lab environment) and not fit for humans or the environment to interact with.
Also, the stimulus says that the dump was established a long time ago, but the rep only tells us that new chemicals are tested for safety. Maybe the standards used to be very lax or even nonexistent, and there are untested chemicals in the dump.
Answer choices
This doesn't weaken that the leak is safe, just shows an irrelevant situation where pharmaceutical regulations could delay the release of drugs to the market.
This doesn't weaken that the leak is safe. The chemicals entering the river could still be highly toxic.
This seriously weakens that the leak is safe - the dump has been around for a long time, so it may contain dangerous chemicals from before the laws went into effect.
This doesn't weaken that the chemicals are safe. Maybe it's even slightly safer because of dilution (not saying I would trust this water, just pointing out that this definitely doesn't weaken the representative's case).
This doesn't tell us anything about if we should be concerned about the leak. This just tells us that there could be other problems with the river, which are irrelevant to the conclusion.