A blaze that engulfed two storage units at the LyondellBasell polyolefins site at Berre in southern France in the early morning hours of Jul. 14 may have been deliberately set, authorities in the district of Bouches-du-Rhône said.

According to LyondellBasell, the fires that began simultaneously around 3 a.m. on the French national holiday and were extinguished around during the late morning hours claimed a gasoline and a naphtha storage unit at the site but had no effect on the site’s production facilities.

The Rotterdam-based and Texas-managed chemical group said it is too early to speculate whether arson was the cause. The tanks are about 500 m apart.

France is on top security alert after several recent terrorist attacks, including a beheading at an Air Products facility near Lyon. Authorities said there was little risk of serious environmental or health effects from the Jul. 14 blaze.

LyondellBasell’s Berre complex houses a steam cracker, a butadiene extraction unit and world-scale polypropylene and polyethylene plants.