How to use if statement to determine whether a block does damage or not?

A part can only do damage if it is programmed to do so, if you want to check whether it can, use a conditional to check for the Script's name, or if it is active.

local Part = workspace.Part

if (Part.ScriptName) then
   if (part.ScriptName.Active) then
        print(Part.Name.." does damage")
   return end
   print(part.Name.." doesn't damage")
end

Explanation

When you write if-then statements, keep in mind that organizationally, you also have access to elseif which defines a separate boolean check from your first case (defined by the first if-then) as well as else for any other cases not explicitly defined

In my below example, I'm assuming that "orange" would refer to the specific BrickColor "Deep orange", you can also check the Color Property of a part and match it against a Color3.fromRBG(#, #, #) if you wanted a specific value or range.

Below, I use a Touched event to get the part that touched your part and check that it exists, as well as has a parent that is also a character instance (this is done so that only Player Humanoids are damaged)

TakeDamage is a function of the Humanoid class that you can use to reduce the player's Health

Server Script Example

local part = script.Parent

part.Touched:Connect(function(hit)
    if hit and hit.Parent and game:GetService("Players"):GetPlayerFromCharacter(hit.Parent) then
        local humanoid = hit.Parent:FindFirstChildOfClass("Humanoid")
        if humanoid then
            if part.BrickColor == BrickColor.new("Deep orange") then
                -- Nothing
            else
                humanoid:TakeDamage(100)
            end
        end
    end
end)

The above code would be placed in a Server Script directly parented under the part you want to damage / not damage players