Use Natural colours only.
Let's use herbal colours made by using Chandan, Haldi, Palash!
The major purpose of holi colour application by friends on each other is to make deep cleansing of the body compulsory. The purpose of the holi is to make skin beautiful. Chandan was recommended for application during holi in our ancient scriptures.
Holi festival is meant to encourage marriage among unmarried and love among married couples. The purpose is birth of children which provides strength to the society. Holi is children's festival. Holi Dahan shows the energy of children that can kill demons even when adults cannot do it. So every society must have fresh young people every year coming into it. For this purpose they have to promote marriage and love. Holi is a festival to pray to love gods. What is prayer? It is an affirmation to develop a particular aspect related to the prayer in us and in our society. Society tells all its members to do certain things and all persons agree to it. All mantras of prayers are meant for this purpose.
Don't spoil the health of your friends with dangerous colours. The purpose is not colour. The purpose is to apply a power that helps your friends to clean their body more deeply. Think of the purpose and make arrangements accordingly. Consult doctors or involve doctors in production of holi powders. Medical shops should sell holi powders.
Think of Holi festival as a festival in which you help your friends not harm them.
For holi festival, people are supposed to eat fresh mangoes and also energetic food. Only energetic food gives healthy babies.
होली : रंगों का त्योहार - About Holi in Hindi
Holi - Festival of Renewal - Festival of Family Life and Children