How to add a message about the danger of the goods to the shipping label?

sample picture

I use UPS API to create a shipping label. For parcels containing dangerous goods, I must add a message, as in the picture. The problem is that I can not find how to add a message?

Solution

So I wrote in UPS and got the answer that it can not be done through API. And the text in the picture needs to be added when processing the received image from UPS. I hope someone will help my answer.