LUFKIN, Texas (AP) -

East Texas authorities are trying to determine how a 2-year-old girl drank so much liquor that her blood alcohol content reached 0.18 percent.

That's more than twice the legal limit for adults to drive in Texas.

The Angelina County Sheriff's Office said the girl, whose name wasn't released, was in serious but stable condition Tuesday at a Houston hospital. A couple watching the toddler at their home near Central, while her parents were out of town, took the girl to a Lufkin hospital Monday afternoon.

Lt. Pete Maskunas said investigators believe alcohol mixed with another beverage was in the toddler's sippy cup.

An infant at the home has been placed with Child Protective Services. Maskunas had no information on whether the youngsters are related.

No charges were immediately filed.