LSAT Explanation PT 38, S4, Q5: Toxicologist: A survey of oil-refinery workers

LSAT Question Stem

Each of the following, if true, strengthens the toxicologist's argument EXCEPT: 

Logical Reasoning Question Type

This is a Strengthen question. 

Correct Answer

The correct answer to this question is B. 

LSAT Question Complete Explanation

Let's first analyze the argument in the passage. The toxicologist claims that due to the high incidence of health complaints among oil-refinery workers who work with MBTE, we can expect an increased incidence of headaches, fatigue, and shortness of breath when gasoline containing MBTE becomes widely used. The structure of the argument is as follows:

Premise: Oil-refinery workers who work with MBTE have a high incidence of health complaints (headaches, fatigue, and shortness of breath).

Conclusion: We can expect an increased incidence of these health complaints when gasoline containing MBTE becomes widely used.

To make this argument more accessible, let's use a simple example. Suppose we have a group of people who work with a certain type of paint that contains a specific chemical. We notice that these people have a high rate of skin rashes. If this paint becomes widely used, we might expect an increased incidence of skin rashes in the general population.

Now, let's come up with an "Evaluate" question: "Is the exposure to MBTE in gasoline similar to the exposure experienced by oil-refinery workers?"

The question type for this problem is Strengthen, and we are asked to find the answer choice that does NOT strengthen the toxicologist's argument. Let's examine each answer choice:

a) Most oil-refinery workers who do not work with MBTE do not have serious health problems involving headaches, fatigue, and shortness of breath.

- This answer choice strengthens the argument by showing that the absence of MBTE is correlated with the absence of the mentioned health complaints. Thus, it is not the correct answer.

b) Headaches, fatigue, and shortness of breath are among the symptoms of several medical conditions that are potentially serious threats to public health.

- This answer choice introduces alternate causes for the health complaints, which weakens the argument. Therefore, this is the correct answer.

c) Since the time when gasoline containing MBTE was first introduced in a few metropolitan areas, those areas reported an increase in the number of complaints about headaches, fatigue, and shortness of breath.

- This answer choice strengthens the argument by showing a correlation between the presence of MBTE in gasoline and the increase in health complaints. Thus, it is not the correct answer.

d) Regions in which only gasoline containing MBTE is used have a much greater incidence of headaches, fatigue, and shortness of breath than do similar regions in which only MBTE-free gasoline is used.

- This answer choice strengthens the argument by showing a correlation between the presence of MBTE in gasoline and the increase in health complaints when compared to regions without MBTE. Thus, it is not the correct answer.

e) The oil-refinery workers surveyed were carefully selected to be representative of the broader population in their medical histories prior to exposure to MBTE, as well as in other relevant respects.

- This answer choice strengthens the argument by showing that the data used to make the argument are accurate and representative of the broader population. Thus, it is not the correct answer.

In conclusion, the correct answer choice is (B), as it does not strengthen the toxicologist's argument and introduces alternate causes for the health complaints.