We love the summer sun, but it can be deadly. The UK’s former chief scientist, David King, has warned this intense heatwave could cause up to 10,000 excess deaths. Despite decades of warnings from scientists that climate breakdown would bring severe heatwaves to the UK, we are still unprepared. Our buildings, public spaces, rules and laws were made for a different climate in a different century. Extreme heat and stormier winters are becoming the norm in Britain, and we’re struggling to cope. As record temperatures pass 40C (104F) in the UK, working people deserve to be safe. Builders, postal workers and street cleaners who spend long periods outside in high temperatures are at serious risk of sunstroke, heat stress and skin cancer. Other workers doing physical labour in indoor heat, like packing in a hot warehouse, can also suffer heat stress, respiratory problems and even heart failure. Working under pressure in these temperatures can reduce people’s capacity to concentrate and lead to deadly accidents. This can be especially dangerous in industries such as transport and construction, and in manufacturing plants. Class shapes who is most at risk from the health risks caused by the climate crisis. People in low-paid and insecure jobs and those on zero-hours contracts find it harder to complain or raise safety concerns because they fear losing their wages. There are legal minimum working temperatures in the UK, but no legal maximum. This defies common sense. Spain, Germany and China all have maximum working temperatures enshrined in workers’ rights. And hotter countries adjust work patterns so workers can avoid the worst heat. The TUC is calling for 30C as a new absolute maximum indoor temperature to indicate when work should stop, or 27C for those doing strenuous jobs. We also want a new legal requirement for employers to take action to reduce temperatures if they exceed 24C and workers feel uncomfortable. And employers should be obliged to provide workers with sun protection and water. Overheating workplaces are not inevitable. While there are not yet maximum legal working temperatures, employers still have a legal duty to provide a safe working environment. This week, they should be cooling down and ventilating workplaces, providing more breaks, adjusting shift patterns and offering water and shade. Crucially, employers should consult their workforce and union reps about how to keep staff safe and comfortable. We all know there are too many bad employers out there who don’t listen to their workforce and won’t take the necessary action to keep them safe. Where workers are at serious or imminent danger due to the heat, Section 44 of the Employment Act allows them to leave an unsafe workplace. It’s important that workers take advice from their union first to try to resolve the problem and to make sure that any walkout is lawful. This is why every worker is safer and stronger in a union. Workplaces with the best health and safety standards tend to be those that are unionised. It’s hard for a single person to ask an employer to take action on their own. By organising together, you can gain union recognition. This means that your employer will be legally required to consult union reps on health and safety, and to negotiate with staff unions to address any problems. If we’re going to avoid even worse heatwaves than the current one, we urgently need to speed up climate action in order to reach net zero. The gas price crisis is pushing millions of people into fuel poverty, many of whom will hesitate to run a fan in July or turn the heating up in January. We need an energy system reformed around the public good that puts people’s needs ahead of private profit. We also need greater investment in clean energy. Together, these would reduce both emissions and bills. Ensuring that workers are safe from dangerous heat levels isn’t difficult. It requires a change in the law. Heatwaves like this will become more frequent and more intense, as will winter storms. We need to adapt to our changing climate, ensuring workplaces are fit and safe for these new extremes. Mika Minio-Paluello is policy officer for climate and industry at the Trades Union Congress and an energy economist with Transition Economics