FIRST a tsunami of steel—next a flood of what? Industrialists all over the place might look nervously at China’s cooling economy and ask that question. The global glut in steel is most alarming because China’s industry dwarfs all others and its mills could easily produce more. Yet other sectors also have existing or looming gluts.

One is coal. Thanks to a massive expansion now under way, China’s coal industry could have 3.3 billion tonnes of excess capacity within two years, reckons Fitch, a rating agency; domestic consumption is less than 4 billion tonnes a year and dropping. Traditionally China has imported, not exported, coal—but that could change. Shenhua Energy, the country’s biggest coal miner, says it might export 10m tonnes soon, up from 1.2m tonnes last year.

Another possibility is aluminium. Chinese smelters push out over half the world’s supply of the metal, thanks to an expansion that goes on despite the current global oversupply. China Hongqiao, the world’s biggest producer, plans to increase capacity to 6m tonnes, up from 5.2m a year ago. The output of Chinese aluminium has sent global prices plunging, hurting rivals. Yet a large part of the cost of making aluminium is in the energy consumed. Just as China might end up wary of exporting coal, it might also shy away from exports which, in effect, also mean exporting energy.

Over-capacity within the oil refining industry also poses a threat beyond China’s shores. Shanghai Securities, a broker, estimates that the country has more than 200m tonnes of overcapacity today. In 2014 Chinese refiners were thought to be running at just two-thirds of capacity. Diesel exports leapt 79% to over 7m in 2015. China National Petroleum Corp, a state energy giant, forecasts that total net exports of all oil products will rise by 31% this year to 25m tonnes.

Chemicals could be another glut candidate. Some 25,000 chemicals firms exist in greater China—though it is worth keeping in mind that statistics on Chinese business are best served with generous pinches of salt. Many of those firms are copycats cranking out commodity chemicals. For most of the 16 main types of chemicals, ranging from purified terephthalic acid (PTA) to acrylic acid, factories have been running well below capacity. Even so, Chinese firms are still increasing their potential output. For example, the capacity for making PTA, a polyester feedstock, has risen by 200% over the past five years. This flood has swept away the profits of Japanese rivals.

Other industries also have grand overcapacity, but most will pose no global threat. China’s state-owned enterprises have many under-used factories that make cars, for example, but these are so shoddy that few people want to buy them abroad.