MedlinePlus recommends that you perform the following steps to administer first aid for chemical burns:
You should first remove the cause of the chemical burn. Do not come in contact with the chemical yourself. In case it is a dry chemical, brush off the excess taking care to avoid your eyes.
Remove any contaminated jewelry or clothing.
Flush the chemicals off the affected area using cool water for 15 minutes or more.
If the victim appears faint or pale, or if there is rapid or shallow breathing, treat him/her for shock.
Apply cool, wet compresses to relieve the pain.
Wrap the affected area with a clean cloth or dry sterile dressing and keep the area away from friction and pressure.