As You Sow initiated an enforcement actions against many national manufacturers, lessors and distributors of portable classrooms regarding indoor air emissions of formaldehyde and other volatile organic compounds from construction materials that required a warning under Proposition 65.

In 2001, over a dozen national companies reached an agreement with As You Sow that included commitments to begin using alternative building materials that will result in exposure to fewer toxic substances including those sometimes contained in engineered wood products, adhesives, caulks, tapes, mastics and glues.

The manufacturers also agreed to provide ventilation in the sub-roof areas on all products ordered for manufacture after July 1, 2001, and to issue advisories regarding the availability of alternative materials and the advisability of airing out the buildings upon installation and prior to occupancy. The settlement ensures that California's modular buildings are now constructed with more environmentally friendly building materials and will reduce the use of and possible exposures to formaldehyde and other toxic compounds.

Subsequently, the California Air Resources Board and Department of Health Services conducted a comprehensive study of portable classrooms throughout California. The study examined not only volatile organic compounds or Proposition 65 chemicals but also the overall environmental health conditions including issues relating to mold contamination, adequate ventilation, temperature control and application of pesticides. A final report entitled "Environmental Health Conditions in California's Portable Classrooms" was provided to the California State Legislature in November 2004.