The follow-up emergency notice requires the owner or operator of a facility that has released a reportable quantity of a substance requiring Section 304 notification to relate, in a follow-up notice, "any known or anticipated acute or chronic health risks associated with the release."  Since general health information is already given on a material safety data sheet (MSDS) for the chemical, will an indication that "severe adverse health effects may be expected" suffice for this requirement?

No.  The health information contained in an MSDS is not specific enough to be of use health professionals, especially if the chemical name is confidential on the MSDS.  However if the MSDS does contain specific information, it should be reported in the follow-up emergency notice.