The suspect, identified as 33-year-old Bryan Riley, shot and killed a 40-year-old man, a 33-year-old woman and her three-month-old son in a residential area in Polk County, Florida, said County Sheriff Grady Judd. The fourth victim was the child's 62-year-old grandmother.

The aircraft dispatched from Texas will gather data on the Phillips 66 refinery and other priority sites, an EPA spokesman told Reuters.

Nearly all New York City subway lines were suspended late on Wednesday as the remnants of Tropical Storm Ida brought drenching rain and the threat of flash floods and tornadoes to parts of the northern mid-Atlantic, CNN reported earlier.

The storm killed at least four people, officials said, a toll that might have been much larger if not for a fortified levee system built around New Orleans after the devastation of Hurricane Katrina 16 years ago.

Ida slammed into the Louisiana coast as a Category 4 storm but had weakened to a Category 1 by early Monday.

Ida was due to make landfall on Sunday, 16 years to the day Hurricane Katrina devastated the southern US city, flooding 80 percent of New Orleans, and leaving behind 1,800 casualties and billions of dollars in damage.