You just have to click on the "Find Your Ship" link at the site that Seabat posted, and there you will find that any ship with the designation of LST, among many others, is considered part of the list. Not very intuitive for the way most people use websites, but the information is there.
Clicking Find Your Ship takes you to this page:
Here is some of what you will find there, and the bottom of the home page provides information on how to make a claim if you were on one of the ships.
Find your ship
Ships or boats that were part of the Mobile Riverine Force, Inshore Fire Support (ISF) Division 93 or had one of the following designations operated on the inland waterways of Vietnam. Veterans whose military records confirm they were aboard these ships qualify for presumption of herbicide exposure.
During your Vietnam tour, did your ship or boat have one of the following designations?
LCM (Landing Craft, Mechanized)
LCU (Landing Craft, Utility)
LCVP (Landing Craft, Vehicle, Personnel)
LST (Landing Ship, Tank)
PBR (Patrol Boat, River)
PCF (Patrol Craft, Fast or Swift Boat)
PG (Patrol Gunboat)
WAK (Cargo Vessel)
WHEC (High Endurance Cutter)
WLB (Buoy Tender)
WPB (Patrol Boat)
YFU (Harbor Utility Craft)