The school investigated and determined that the disinfectant solution used, was not properly wiped from the toilet seats the previous night. The school advised in a letter sent home with students (PDF) that the chemical used is Dayquat256.
Dayquat256 is manufactured by Daycon Products Company in Upper Marlboro and is classified as a “concentrated disinfectant cleaner” and described as a green liquid with a minor alcohol odor. The chemical does not appear to be caustic or overly dangerous. According to the MSDS sheet (PDF), first aid for skin exposure is to wash with plenty of soap and water.
In their letter, the school states that the chemical is diluted with water before use, but did not say if the application last night was diluted. The manufacturer recommends a dilution of 1 ounce per 5 gallons of water and claims that there is no rinse needed at this dilution.