The Pakistan Tanners Association (Northern Zone) has expressed concern over the proposed restriction on export of crust leather, terming it an initiative detremental to the export sector. PTA Chairman Khawaja Muhammad Mehr Ali said here Monday the leather industry was among major contributers to the national economy, citing that all over the world leather was recognized as a high value-added industry. The proposed restriction on crust leather export would cause a huge loss of $500 million annual to country’s foreign exchange, while more than 300,000 workers would lose job.