### Question
How is the term machine cavities in operation defined?


### Answer
The term **machine cavities in operation** is defined in *15 U.S.C. § 8702* as the following:

> those machine cavities associated with a block machine that have produced concrete masonry units within the last 6 months of the date set for determining eligibility and is fully operable and capable of producing concrete masonry units

#### Citation:
  - *15 U.S.C. § 8702*
  - Heading: **CHAPTER 113-CONCRETE MASONRY PRODUCTS RESEARCH, EDUCATION, AND PROMOTION**

