Many of the fixatives and stains used in fecal examination preparations are highly toxic, posing a risk to the microscopist. In addition, care must be taken when disposing of these materials, as they pose risks to the environment.

Considering this information and the content studied about laboratory methods applied to parasitology, analyze the following statements:

I. Ethyl acetate is preferable to ether because it is less flammable.
II. Sodium azide, a toxic substance, is used for sedimentation in the Kato-Katz method.
III. The Ritchie method poses a risk to the microscopist, a mask should be used due to the volatility of the reagents.
IV. Malachite green, used in the Kato-Katz method, is a toxic substance.
V. Zinc sulfate, used for reagent sedimentation in the Blagg method, is toxic.

Only what is stated in: