The employee API fills in the background also the CRM parties table, and as a consequence generates also a lot of workflow business events.

When you do NOT use CRM, you can stop these side-actions of the employee API by setting the profile option "HZ: Execute API Callouts" to No (defaulted on Yes)

this query gives you all the Tier I loclaizations/legislations supported by Oracle core dev team:

select
nvl( territory_short_name, 'ZZ International') legislation,
(
Select 'Y'
from hr_legislation_installations li2
where li2.application_short_name = 'PAY'
and li2.legislation_code = li.legislation_code
) payroll
from hr_legislation_installations li, fnd_territories_tl t
where application_short_name = 'PER'
and legislation_code = territory_code (+)
and language (+)= 'US'
order by 2, 1