He said the Environmental Protection Agency had sent a criminal investigator to Texarkana. Part of a junior high school was sealed off Friday when mercury was found on a science room floor. Emergency workers found out Thursday and closed the store. Mercury damages the central nervous system and can cause irreversible learning and speech disabilities. The owner of the neon plant, which shut down in the 1970s, told police the break-in occurred before Dec. 16.
Officials say the delay in symptoms was typical of gradual mercury exposure.
The heavy metal accumulates in the body every time it's handled.