This purchase was as a substitute for the Carhartt B167, which has been discontinued due to "lack of customer interest", per a Carhart customer service person. She also told me that this style, the Loose Fit Straight Leg #100066, had the same size leg opening as the B167.

From the website:

"Constructed Carhartt strong in heavyweight, 15-ounce, 100% cotton denim, our loose-fit straight-leg jean is the right choice for rugged jobs. A comfortable pick, this five-pocket jean sits slightly below the waist and features a loose-fitting seat and thighs. The leg openings are straight.
  * 15-ounce, 100% cotton denim
  * Sits slightly below the waist
  *Straight leg openings"
That pretty much sounds like the B167. Unfortunately, that is not the case. The fabric is as described and the quality of the construction is good, but on my husband, this is not a loose fit in the seat and thighs. Not even close. Had these been a tad smaller he wouldn't have gotten into them at all. I have not compared the measurements to the B167, but this is no substitute. A size up in the waist might be more comfortable for him in he seat and thigh area, but the length is oddly longer than the same purchased length on the old version.