Air Products facilities in Hometown and the Lehigh Valley are tightening security following a terroristic attack on one of its plants in France.

A truck driver once under surveillance for radical Islamic ties crashed into the chemical warehouse in Saint-Quentin-Fallavier on Friday and hung his employer's severed head on a factory gate, along with banners with Arabic inscriptions.The attack at the Air Products plant, which triggered an explosion that wounded two people, came on a day of violence that spanned three continents.Air Products is headquartered in Upper Macungie Township and has plants locally in Hometown and Trexlertown, as well as facilities throughout the world and is a leader in industrial gas production.Yassine Salhi, who was apprehended soon after setting off the blast, is the latest French citizen implicated in extremist bloodshed in recent years after being flagged to authorities, then falling off the radar.The French attack began about 9:30 a.m., when Salhi drove a utility truck to the gate of the Air Products factory.Prosecutor Francois Molins said Salhi was known to factory staff because he regularly made deliveries there, and they let him in the gate. Once beyond the sight of security cameras, Salhi plowed his truck into gas canisters in a factory warehouse, touching off an explosion.A knife and the decapitated body of Salhi's employer, whose name has not been released, were found at the site of the explosion, and the severed head was posted on a gate at the factory entrance with two flags bearing proclamations of Islamic faith, the prosecutor said.Firefighters apprehended Salhi, and he was in custody Friday night along with his wife, sister and another person, while police sweeps of the vehicle and the suspect's apartment were continuing, the prosecutor said.Air Products Chairman, President and CEO Seifi Ghasemi expressed his deepest sympathy to the victim's family and addressed the attack in a statement published on the company's website this afternoon."I am horrified and saddened by the attack on our facility in France," he said. "I believe I speak for all of our Air Products family around the world in expressing our deepest sympathies to the family of the victim of this unspeakable act."My heart also goes out to the people who work at the site and their families. This incident reinforces that we all need to take safety and security very seriously, every day, and remain vigilant in everything we do. I am very glad to know that all of our employees are safe and accounted for."Soon after the attack, French authorities and emergency services arrived on site and contained the situation. All individuals working at the site were evacuated. Air Products' crisis and emergency response teams were activated and are working closely with involved authorities."I would like to express my appreciation for the response of the French and other authorities who reacted so quickly to our need. I would also like to express my deepest gratitude to other companies, customers, elected officials, and many other citizens of the world who have reached out to Air Products with kind words, well wishes, and offers of assistance," Ghasemi said.No group immediately claimed responsibility for the factory attack in France. The severed head appeared to mimic the Islamic State group's practice of beheading prisoners and displaying their heads for all to see, and came days after the militants urged attacks during the Muslim holy month of Ramadan.It is unclear at this time the extent of damage to the facility. However, Ghasemi said other facilities are operating normally, and plans are in place for Air Products' customers who received products from the impacted location to continue to be served.The attack in France came on the same day that a gunman mowed down scores of European tourists on a beach in Tunisia and a suicide bomber killed more than two dozen worshippers at a Shiite mosque in Kuwait - violence that followed a call by Islamic State extremists to target "nonbelievers."No further details were released about the two people injured in the explosion.The Associated Press contributed to this story.