This Passover, the citizens of Haifa were delivered from a deadly plague — the threat of mass casualties due to an ammonia explosion. And they were freed from the bondage of imminent terror, not so much by an outstretched arm, nor by a Moses, but rather by a group of chemistry professors.

A simple act of sabotage against a ship carrying ammonia in their harbor or a direct rocket hit at Haifa Chemical Corporation’s ammonia tank could have released thousands of tons of a deadly chemical into the atmosphere, killing or maiming untold scores of people. Happily, a series of recent events brought this untenable situation to an end and is delivering Haifa’s citizens out of a perilous, toxic limbo.

The recent court decision to close the Haifa Chemical Corporation’s ammonia tank and limit delivery of ammonia by sea to Haifa did not happen by itself. For those unfamiliar with the details, a brief synopsis of the of Haifa’s latest petrochemical drama looks like this: Ammonia – NH4, is a common chemical with one molecule of nitrogen (N) and three of hydrogen (H3). Natural ammonia background levels do not pose a danger to humans. But for many years now, humans produce far more ammonia than does nature (largely for fertilizers). Industrial quantities of ammonia constitute an extremely dangerous chemical.

Ammonia is highly corrosive with a strong and irritating odor even when minuscule quantities are in the air. When the chemical comes in contact with the skin, eyes, respiratory tract and digestive tracts it burns ferociously. If atmospheric levels reach 0.5% — ammonia causes death within 10 to 15 minutes; at lower concentrations, it causes paralysis.

For over three decades, copious quantities of ammonia have been regularly delivered and stored in a massive, 12,000-ton tank near the Haifa Chemical Corporation plant in the heart of Haifa’s Krayot suburbs. The chemical was deemed critical for the company’s massive manufacturing of fertilizers.

Haifa Chemicals runs a highly profitable, $700 million operation. Since 1989 the company has been owned by an American conglomerate controlled by Jules Trump with some 600 employees. Given the pace of production required to supply a third of the world’s Potassium Nitrate, the ammonia tank that feeds the factory’s chemical processes empties on a regular basis. And so, each month for over thirty years now, it is restocked by a tanker carrying 16,700 tons of ammonia that sails into Haifa Bay.

Concerns about the impact of an attack on the ammonia tank became newsworthy in 2006, during the Second Lebanon War. For weeks, the IDF proved incapable of stopping the hailstorm of Katyusha rockets falling into the Haifa area. Alarm about the safety of residents was exacerbated after Hezbollah leader, Hassan Nasrallah intermittently confirmed how tempting the Ammonia facility was as a target for the 10,000 long-range rockets his terrorist organization stockpiles in Lebanon.

Until recently, the risk posed by the ammonia deliveries was deemed less salient. But the truth is that a simple shoulder-fired bazooka could easily penetrate the ammonia bearing ship docked in a largely unprotected port, sending tons of the hazardous gases into the air.

When challenged why such hazards should be tolerated, Haifa Chemicals dismissed disaster scenarios as delusional, while claiming that ample ammonia supply was critical for innumerable Israeli industrial sectors. For some twenty years, environmental groups were not assuaged and called for immediate closure of the tank. After Haifa mayor Yonah Yahav, was first elected, some 14 years ago, he too expressed discomfort with the facility and called for its removal to the south with its lower population densities.

The Ministry of Environmental Protection, however, was less consistent in its opposition. For instance, in 2011 it endorsed a report which bought into the corporation’s contention that the facility was absolutely critical to the country’s agricultural and industrial prosperity.

But one person was keenly aware of at the high stakes gamble taking place in Haifa bay and literally could not sleep at night. Ehud Keinan is one of Israel’s most eminent chemists: a former dean of the Technion chemistry faculty, he also heads the country’s Association of Chemists and chairs the Israel journal of chemistry. With over 170 peer-reviewed articles and three books, his considerable energies hare typically focused on experiments and publications.

But Professor Keinan also lives in Haifa. The more he learned about the risk posed by the local ammonia operation, the less he was able to sleep at night. The issue gave him no rest. To prove his point he even drove into the port on four separate occasions to demonstrate how astonishingly easy it might be for a hostile terrorist, acting alone to create death and destruction.

Such concerns did not go entirely unheeded: In 2013 Israel’s government called for the creation of a new ammonia plant in the Negev which would replace the Haifa facility. But such a factory was not sufficiently lucrative to generate any meaningful bids and in November 2016 the Ministry of Environmental Protection announced the tender to be a failure. Haifa Chemicals continued on — business as unusual — with no attempts to seek alternative production processes or relocate given security concerns.

It was then that Keinan was appointed by Haifa’s mayor to prepare a definitive report on the risks posed by ammonia in Haifa Bay. Keinan took the challenge on the condition that he and his colleagues receive absolutely no pay, thus avoiding any claims of bias. He then assembled a virtual dream team of ten leading Israeli chemical professors, including Israel’s venerable Nobel Chemistry Prize laureate, Dan Shechtman and began writing. Working at uncharacteristically efficacious tempo and supported by dozens of their engineering colleagues, by January, 2017, the committee’s meticulously documented 107-page report was released.

The picture it paints sounds like a Hollywood disaster movie. A direct hit to the Haifa ammonia tank could generate a plume that would lead to the acute poisoning of some 16,000 people. Of far greater magnitude was the risk posed by an act of sabotage to ammonia bearing ships. Here, atmospheric dispersion models showed the number of casualties to reach into the hundreds of thousands, a disaster of unprecedented dimensions.

The report explains that while Haifa Chemicals propagandizes about its factory being a nationally critical, strategic facility, in fact, its aggregate, societal benefits are overstated. At most, some 3% of the ammonia imported is needed by local Israeli industry; The remaining 97% ends up leaving Israel in the form of fertilizers which are typically sent to India or Turkey. The scientists ask rhetorically: Why should the Israeli government prioritize such a potentially explosive operation– in order to help subsidize an American corporation’s overseas production?

Mayor Yahav, with the strong support of the vociferous Green Party council members finally had the evidence and expert witnesses he needed to take action independent from a central government in which they had little confidence. The city wasted no time in filing a legal action calling for enjoining ammonia storage and delivery.

It soon clear that the tide had turned. In response to the scientists’ verdict and a furor in the press, Israel’s governmental agencies began to stutter and backtrack on their knee-jerk support for manufacturing profits. More importantly, the court wasn’t buying the traditional complacency. When the matter came before her, Judge Tamar Sharon Netanel chose to listen to the scientists. She immediately ruled that the tank be emptied by April 1, 2017 and prohibited its refilling and all future ammonia deliveries to Haifa Bay: “I am not unaware of the damage that this judgment will cause to third parties and I am aware that there are no magic solutions. The probability of an actual occurrence in which hundreds of thousands of people are seriously harmed just trumps the economic and business interests.”

Faced with imminent closure, Haifa Chemicals pursues a last-ditch legal appeal. To its discredit, the government along with the Ministry of Environment resorted to the role of collaborators. But it was during Passover itself that Supreme Court ruled that the game is up. The court allowed the entry of a single ship, with limited ammonia cargo under strict constraints, as a one-time measure — but only after presenting the court a range of information, including the availability of alternatives. For Haifa Chemicals’ ammonia operation, “business as usual” is over.

The ostensible resolution of the Haifa ammonia controversy is a reminder that Israel remains a robust, democratic society, where informed and determined public vigilance can bring about positive change. An engaged citizenry and an independent mayor who cares about his constituents matter. Then again, perhaps it is a little bit miraculous that such erudite and tenacious patriots can be found in the vaunted laboratories and ivory towers of Israeli academia.