If there is gasoline in the water, I would say no. A healthier alternative may be using neem oil to kill the mosquito larvae. You may wish to do some research to find if Neem does kill the larvae.
We have a thread on Neem Oil in the General Forum (I think). But, I'm thinking that you may wish to look up some other sources on the web.
Mosquito dunks are Bt and will kill the larvae. You will need to assess how much water and how many dunks, but much safer I would think. Then again, if a screen would do the trick that would be the best idea.