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Tier2 Submit validation error due to incorrect CAS number

What do I do if I get a validation error in Tier2 Submit due to an incorrect CAS number?

First, review your source information to see if the CAS number was typed in incorrectly (for example, a missing digit or two digits typed in the wrong order). Second, consider looking up the chemical in the EPA Substance Registry Services, CAMEO Chemicals, or another database to see if you can identify the correct CAS number. Third, you can also leave the field blank, since the CAS number field is not mandatory. You should also make sure the chemical name is entered properly.