3
_more important categories. Of those 18, all but one also
have non-IBT data available in some or all of the same
cagetories. The exception, prometon, a herbicide not used
_on food crops, has one partially valid IBT study. and many Loe
non-IBT acute and subacute studies. Sixteen of these high
volume chemicals are the subject of one of the regulatory
procedures described above requiring additional data.
Thus, the data bases for the high volume chemicals to
which people are most likely to be exposed are for the
most part unaffected by the IBT situation, and where there
. is an impact, EPA has-taken active regulatory steps to }
_ abtain replacement data.

The principal remaining task of the IBT program
is to clarify the status of the invalid studies for which
registrants have indicated they do not intend to provide -
replacements, or have not communicated an intention one way .
or the other to EPA. Atthough around 300.studies are in .
this category, a significant number (140) of negative and .
non-responses involve discontinued or cancelled products,
or pesticides of such low volume use that registrants may
choose not to invest in further testing needed to maintain
registrations. The replacement status column of Exhibit 8B
indicates that there are 159 invalid studies (26% of invalid
IBT tests) for which there is negative or no response. a
However, as previously noted, most of these chemicals have
non-IBT data available. Exhibit A shows that only five
chemicals still registered and actually used have entirely
IBT data bases. The 17 studies involved with those 5
chemicals constitute 3% of invalid IBT studies. A registra-
tion standard will result in replacement of 6 of these
studies. This leaves only 11 studies or 2% of.the invalid
IBT tests which constitute the sole support of registered .
pesticides, and for ‘which no regulatory action to generate
replacement data has yet been initiated. Several of these
11 are valid or have at least supplementary value.

This report is being furnished to the registrants
of the affected chemicals for which negative or no responses .
have been received concerning replacement of invalid IBT
studies. We are also sending the registrants 3(c)(2)(8)
notifications which-require a registrant to make a specific
commitment within 90 days or the registration may be .
suspended. In some cases, EPA and a registrant may agree
that a specific study does not need to be replaced.

The IBT case caused serious concern and uncertainty.
about the potential hazards of the hundreds of pesticides
involved, both for EPA and the public. Although it was .
advocated by some that all 212 pesticides tested in whole
or in part by IBT be removed from the market pendihg , -
retesting, that option is not. available under current law. __.