I just found the answer to my own question. See the link below for more horror stories, it's apparently just as bad as E. marginata. :(

Here is a link that might be useful: Euphorbia myrsinites

Steve,
I use the E. marginata and actually usually don't wear gloves. It does have the sap and I am careful, but haven't had the issues described in your link. I have another spring blooming euphorbia that also has the sap, that I use with tulips. No problems there either.

I think properly handled, it can be ok.

Well, maybe I'm being overly cautious. I've had Euphorbia myrsinites growing in my garden for years and have gotten the sap on my hands when cutting it back with no ill effect for me. I do like the chartreuse flowers.

Just as with most things, the sap on euphorbias can cause very allergic reactions in some people and nothing in others. It just depends on the person's sensitivity to it. Never has done anything to me so far anyways. Not sure, but perhaps you can sear the ends of the stems to prevent those who are susceptible to it from getting the effects. I have also read something somewhere that the sap from these plants can cause other flowers in a boquet to wilt so am not sure I would be putting them in a mixed bouquet before I checked into that.

I grow donkey tail spurge as well and it reseeds quite prolifically for me.

{{gwi:587032}}

Also like euphorbia characias subspecies wulfenii, another reseeder for me.

{{gwi:587031}}

I nearly went blind from the sap of a pencil cactus (really a euphorbia) just touching my eyes after handling the sap and washing my hands. The sap is latex based and I am allergic to latex. It was though lye was thrown in my eyes and burned out both of my corneas. By the time I got to the ER I was blind and in the most pain I have ever been in in my life. I spent three days in agony even on Vicodin. My internal eye pressure had to be checked for months after to make sure I did not become blind. How will you know if you are dealing with a latex allergy? I would not ever touch a euphorbia. If you get the sap on your hands soap does not get it all off because of the latex base. Milk binds with latex. I poured a gallon in my eyes after the visit to the ER because they flushed with water and that does not always get it all out. The eye specialist I went to said it was one of the worst chemical burns she had ever seen. The pencil cactus will burn out anyones eyes it is so toxic. They sell this so called cactus in garden centers so beware especially if you have kids or pets. If you have one of these get RID of It and wear gloves. I would not want my worst enemy to suffer the pain I went through. Agony, along with the fear I would never see again. Dont chance selling a euphorbia in a flower arrangement, you will not know who may have a latex allergy. Or have really good insurance.