Mike:
The EPA has made no such mandate. The ZDDP in any "starburst"
oil has been reduced to 800 PPM. This is plenty for all current detroit production (roller everything). For the rest of us with non-roller everything it would be wise to use an
oil with a higher amount (at least 1200PPM) of ZDDP.
Myself, I'm using Redline 5W-30 (non-racing)
oil which has 1,200 PPM ZDDP. I'm not sure what other brands have the higher ZDDP in the thinner viscosity I prefer. All the heavier oils have it.
Bob