for US EPA to add Dichlorofluoromethane to the Toxic Release
are known to release chlorine radicals into the stratosphere.
Chlorine radicals act as catalysts to reduce the net amount
of stratospheric ozone.
ozone shields the earth from ultraviolet-B (UV-B) radiation
(i.e., 290 to 320 nanometers). Decreases in total column ozone
will increase the percentage of UV-B radiation, especially
at its most harmful wavelengths, reaching the earth's surface.
to UV-B radiation has been implicated by laboratory and epidemiologic
studies as a cause of two types of nonmelanoma skin cancers:
squamous cell cancer and basal cell cancer. Studies predict
that for every 1 percent increase in UV-B radiation, nonmelanoma
skin cancer cases would increase by about 1 to 3 percent.
epidemiological studies, including large case control studies,
suggest that UV-B radiation plays an important role in causing
malignant melanoma skin cancer. Recent studies predict that
for each 1 percent change in UV-B intensity, the incidence
of melanoma could increase from 0.5 to 1 percent.
have demonstrated that UV-B radiation can suppress the immune
response system in animals, and, possibly, in humans. Increases
in exposure to UV-B radiation are likely to increase the incidence
of cataracts and could adversely affect the retina.
organisms, particularly phytoplankton, zooplankton, and the
larvae of many fishes, appear to be susceptible to harm from
increased exposure to UV-B radiation because they spend at
least part of their time at or near the surface of waters
UV-B penetration has been shown to result in adverse impacts
on plants. Field studies on soybeans suggest that yield reductions
could occur in some cultivars of soybeans, while evidence
from laboratory studies suggest that two out of three cultivars
are sensitive to UV-B.
this increased UV-B radiation can be reasonably anticipated
to lead to cancer and other chronic human health effects and
significant adverse environmental effects, EPA believes there
is sufficient evidence for listing the following HCFCs that
are commercially viable on EPCRA section 313 pursuant to EPCRA
sections 313(d)(2)(B) and (C). EPA is proposing that the following
HCFCs be added individually to EPCRA section 313:
USEPA/OPPT. Support Document for the Health and Ecological
Toxicity Review of TRI Expansion Chemicals. U. S. Environmental
Protection Agency, Washington, DC (1993).
cited by US EPA in:
Register: January 12, 1994. Part
IV. 40 CFR Part 372. Addition of Certain Chemicals; Toxic
Chemical Release Reporting; Community Right-to-Know; Proposed