Three workers died in a maintenance accident at a gas plant at the Zelten oil and gas field, the Libya Observer reports.

The workers suffocated after being exposed to hydrogen sulfide (H2S), the newspaper reports.

A fourth worker is being treated in a local hospital, according to Reuters.

The field and plant are operated by Sirte Oil and Gas Company. The field produces 35,000-40,000 barrels per day, the news agency reports.