An ammonia leak struck an Emek Hefer factory on Tuesday night, for the second time in less than a year.
Police said that the leak was minor and that there were no casualties. There was no apparent harm to the factory.
Four firefighting teams were deployed to the Hod Hefer poultry processing factory, on Israel's coastal plain, along with experts trained for dealing with dangerous materials. The firefighting forces said that the leak occurred during maintenance work on a pipe.
Route 4, a major artery, was closed to traffic in both directions.
In November of last year, a firefighter was killed and twenty were injured after inhaling ammonia gas released from a 60-ton container at the same factory.
Ammonia, a colorless but strong-smelling gas comprised of nitrogen and hydrogen, is a naturally occurring chemical compound that is also mass produced for industrial use. It serves as a raw material for various products and also as a warehouse refrigerant.
Ammonia is corrosive and can cause severe irritation of the eyes and respiratory system. In high concentrations, it can cause serious burns, blindness, lung damage and even death.
The vast majority of industrial ammonia in Israel is stored in a large tank in Haifa Bay. From there, it is shipped to various factories, most commonly for use as a refrigerant in food factories.
The leak occurred when a two-to-three centimeter breach opened in the pressurised container, which authorities fear could erupt.