Some, but not all, of the different safety issues are covered in your first two books. For example: contraindications are mentioned in the first book in preparation for your written exam. There is also a continuing education text in your third module, (if you are on the Multi-Payment Option Plan), that touches on these points. The continuing education text is also included in the Camp-in-a-Box version 3.5 and the Scratch and Dent Sale.
If you want a resource that goes completely in-depth on Yoga safety, there is a book called:
B.K.S. Iyengar Yoga The Path to Holistic Health ISBN 0-7894-7165-5.
This is an extremely valuable book. The first time I picked it up and started to read it, I had to have it. It has lesson plans for many special conditions and goes into more detail about props than any Yoga resource on the market.
Some basic guidelines for safely teaching Yoga classes: There are many conditions, but the three most common are limited range of motion, high blood pressure, and pregnancy.
With limited range of motion, you encourage students to use props. Over time and regular practice, your student’s range of motion will increase.
With high blood pressure, you should discourage inversions and possibly twists, if the condition is severe.
With pregnancy, you discourage twists, prone poses, and inversions. However, Yoga practice for pregnancy is different for each trimester and is more complicated, to say the least. That is why we carry a separate Pre and Postnatal Yoga teacher course for certified instructors, written by Jane Mackarness.
If you want to scratch the surface on this subject Yoga Zone has a pregnancy video that is informative and helpful. Shiva Rea also has informative videos on Prenatal and Postnatal Yoga.