What is the first step to take for dermal exposure to a toxic substance?

The initial step to take for dermal exposure to a toxic substance is to remove contaminated clothing. This action is crucial because the clothing can continue to absorb the toxin or irritant, prolonging skin contact and potentially worsening exposure. By removing the contaminated garments, you can significantly reduce the risk of further skin absorption of the harmful substance.

It's important to note that subsequent steps, such as washing the skin with soap and water, are also vital. However, these should occur after ensuring that contaminated clothing is no longer in contact with the skin. Wrapping the affected area in a bandage or applying ointment might be appropriate in certain situations, but these actions could trap the toxic substance against the skin rather than facilitating its removal. Thus, the immediate priority is to eliminate any source of contamination by taking off the clothing before proceeding with decontamination measures.