Prestone AS250 De-Icer Windshield Washer Fluid

The product label states −34°F protection. SDS Section 9 confirms a freeze/melting point of −34.4 to −27.2°F, which is consistent with the label claim. This puts it in the premium winter tier — adequate for all but the most extreme northern US and Canadian climates.

Yes. SDS 546 (November 2022) lists methanol (CAS 67-56-1) at 20 to less than 35% by weight as the primary active ingredient. This is the standard chemistry for a winter de-icer washer fluid. The DANGER signal word and Proposition 65 warning on the label both stem from the methanol content.

No. Prestone AS250 is not for sale in California, Texas, or Maricopa County, Arizona due to CARB consumer product VOC regulations that restrict methanol in consumer products. Residents of those areas should look for a methanol-free or ethanol-based washer fluid that complies with CARB VOC limits.

The Amazon product listing states the formula is safe for rain-sensing technology windshields. However, because this is a methanol-based formula — not an alcohol-free or surfactant-based formula — verify with your vehicle manufacturer if you have concerns about sensor compatibility.

Methanol ingestion is a medical emergency. The SDS classifies this product as H301 (toxic if swallowed) and H370 (specific organ toxicity — optic nerve damage). Contact Poison Control (1-800-222-1222 in the US) or emergency services immediately. Do not induce vomiting. Keep the product out of reach of children and pets.