CHANGZHOU, China — On a dusty lane in east China, a small factory sitting amid strawberry and vegetable fields processes chemicals from pig guts into heparin, a commonly used blood thinner linked to 62 deaths and hundreds of allergic reactions in America and Germany.

The mysterious problems with heparin from the factory and others like it — China’s deadliest product quality scandal since Chinese cough syrup killed 93 people in Central America a year ago — dramatically illustrate the perils of shifting drug production offshore. With recalls of heparin products now in six countries, it is an issue that regulators are scrambling to address.

In the past month, China’s drug safety agency has ordered tighter controls on heparin production. That followed a U.S. Food and Drug Administration order requiring all heparin imports to be tested. The FDA also announced plans to station eight regulators in China and hire five Chinese to work with them.