The Environmental Protection Commission amended Iowa Admin. Code ch. 135, Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks. Changes incorporate new state laws on the investigation and cleanup of petroleum contamination. Changes take effect February 16, 2011. http://www.legis.state.ia.us/aspx/ACODOCS/DOCS/01-12-2011.Bulletin.pdf pp. 1039-40.