State the adverse effects of polyhalogenated compounds. How can the adverse effects of chlorofluorocarbons be prevented?

(N/A) $(i)$ Methylene dichloride: Exposure to lower levels of methylene chloride in air causes dizziness,nausea,tingling,and numbness in the fingers and toes. In humans,direct skin contact causes intense burning and mild redness. Direct contact with the eyes can burn the cornea.
$(ii)$ Trichloromethane (Chloroform): Inhaling chloroform depresses the central nervous system. Chronic exposure may cause damage to the liver and kidneys. It is slowly oxidized by air to the extremely poisonous gas phosgene $(COCl_2)$: $2CHCl_3 + O_2 \xrightarrow{\text{Light/Oxidation}} 2COCl_2 + 2HCl$. It is stored in closed,dark-colored bottles completely filled to exclude air.
$(iii)$ Tetrachloromethane $(CCl_4)$: Exposure causes liver cancer,dizziness,nausea,and permanent nerve cell damage. In severe cases,it leads to coma or death. It also depletes the ozone layer,increasing exposure to $UV$ rays,which leads to skin cancer and immune system disorders.
$(iv)$ Freons: In the stratosphere,freons initiate radical chain reactions that upset the natural ozone balance.
Prevention of adverse effects of $CFCs$: $CFCs$ are stable and non-reactive but deplete the ozone layer. It is recommended that $CFCs$ used in refrigerators be replaced by other environmentally friendly compounds.