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Hazardous Materials Engineer, Class B Category 4 (Otsu-4)

Prepare for Japan's national qualification through the fundamentals of flammable-liquid classification, designated quantities, and the examination system.

This qualification tests the knowledge needed to handle familiar flammable liquids such as gasoline, alcohols, and kerosene safely. Check your grasp of regulations, physics and chemistry, hazardous-material properties, and fire control.

Try the Otsu-4 foundation questions

What does Otsu-4 cover?

Category 4 of the Class B license covers flammable liquids classified as Category 4 hazardous materials under Japan's Fire Service Act. Typical examples include gasoline, alcohols, kerosene, diesel oil, heavy oil, and animal and vegetable oils. Legal classifications and designated quantities are as important as the properties of individual substances.

Subjects and number of questions

The standard Class B examination without exemptions has 15 questions on hazardous-materials regulations, 10 on basic physics and chemistry, and 10 on hazardous-material properties, fire prevention, and extinguishing, for a total of 35. Check the administering body's latest information before applying because examination details and exemption conditions may change.

Eligibility

Anyone may sit a Class B examination, regardless of age, education, or work experience. A candidate who already holds a Class B license for a different category may be able to apply for subject exemptions.

How to study

First learn to distinguish the properties of Categories 1 through 6, then organize the names and designated quantities within Category 4. Next, practise designated-quantity multiples and legal conditions until you can explain the basis for each answer.