WASHINGTON -- In a sharp turnabout, the Ozone Transport Commission today released a updated draft of its model rule for emission reduction, proposing a substantially higher limit than in the previous draft.

The new draft proposes an allowable limit of 150 grams of volatile organic compounds per liter for solutions for cleaning printed circuit boards. That's 125 g/l more than proposed in the previous draft, a number which caused concern among suppliers and users of precision cleaning chemistry.

The modified rule also states a cleaning solution greater than 150 g/l VOC content may be used for PCB cleaning, provided an approved VOC emissions capture and control device is used to control air emissions to the 150 g/l VOC limit.

The model rule was developed by the OTC as part of a regional effort to attain and maintain the one-hour ozone standard, shortfalls that were identified by the US Environmental Protection Agency in specific states' plans. It affects states in the New England and Mid-Atlantic areas, and is modeled on rules implemented in California.

The committee will next meet Sept. 7-8, near BWI Airport in Linthicum Heights, MD. Stakeholders are urged to attend and comment on the proposed rule.