Is pork safe that has been left in water to thaw overnight?

No. Pork should not be left in water to thaw overnight.

Bacteria can grow on the pork at temperatures between 40 and 140 °F (4 and 60 °C). Leaving pork in water to thaw overnight can allow the meat to stay in this temperature range for too long, which could cause bacteria to multiply.

The safest way to thaw pork is in the refrigerator. Pork can also be thawed in a cold water bath, but it should not be left in the water for more than two hours.