I had a few things wrong. The incident happened in 1983, the kid stole
two Gaboon Vipers from the National Zoo, and took them on the bus in a
plastic garbage bag. They did have some antivenom on hand, but it wasn't enough, so they had to fly in more from the Bronx Zoo, and later zoos in Baltimore and Philadelphia. See the story below. As Jack Nicholson said in the movie
The Last Detail, "There are more strange things in this world that you could possibly imagine".
https://www.nytimes.com/1983/04/06/us/zoos-come-to-aid-of-teen-ager-bitten-by-viper-stolen-from-cage-in-washington.html