Pull tab activatable environmental exposure indicators

An activatable environmental exposure indicator, comprising:

• a substrate;
• a first indicator region and a second indicator region defined on the substrate;
• a first reservoir containing a first payload comprising a first liquefiable material configured to liquefy responsive to a first predetermined environmental exposure, a second reservoir containing a second payload comprising a second liquefiable material configured to liquefy responsive to a second predetermined environmental exposure;
• and
• a removable sealing layer, the removable sealing layer preventing flow of the first payload from the first reservoir to the first indicator region when the first liquefiable material is liquefied and prevents flow of the second payload from the second reservoir to the second indicator region when the second liquefiable material is liquefied,
• wherein removing the removable sealing layer permits flow of the first payload from the first reservoir to the first indicator region when the first liquefiable material is liquefied and permits flow of the second payload from the second reservoir to the second indicator region when the second liquefiable material is liquefied, and
• wherein, responsive to an exposure to the first predetermined environmental exposure after the removable sealing layer is removed, flow of the first liquefiable material from the first reservoir to the first indicator region produces a first observable effect,
• wherein, responsive to an exposure to the second predetermined environmental exposure after the removable sealing layer is removed, flow of the second liquefiable material from the second reservoir to the second indicator region produces a second observable effect.