Sturbridge, MA – WPRI -More than a dozen employees of Wal-Mart are recovering today from exposure to carbon monoxide.

The incident yesterday in Sturbridge was the second time a Wal-Mart in Massachusetts was evacuated in the past three months because of airborne emissions.

Thirteen workers and one customer were taken to Worcester-area hospitals after complaining of headaches and nausea at 8:30 a-m.

By ten a-m, the store’s carbon monoxide detectors went off, and managers began evacuating people.

Fire officials arrived and traced the leak to a vent system in the lawn-and-garden section. They said fumes came from the propane heating unit on the roof.

The sickened people were treated and released. The store reopened around midday.

On July first, several dozen people became ill at the Danvers Wal-Mart.