Twenty-four hour notification means telephoning CDPH within 24 hours with prompt follow-up letter when individuals are exposed to an eye dose equivalent within 24 hours exceeding:

• A. 15 rems
• B. 5 rems
• C. 25 rems
• D. 50 rems

Answer: (A)

Exposures to the lens of the eye are closely watched because the eye is especially sensitive to radiation, and a large dose in a short time increases the risk of cataracts. The rule requires notifying the California Department of Public Health within 24 hours whenever the eye dose equivalent a person receives in any 24-hour period exceeds 15 rem. This threshold matches the level at which rapid regulatory communication is triggered and aligns with the annual lens-dose limit for workers (about 150 mSv per year). Therefore, 15 rem is the threshold that prompts the 24-hour notification with a follow-up letter. The other numbers do not fit this specific reporting criterion.