The same rules as above apply here: if you believe there is a threat of danger to you and it cannot be mitigated, you can refuse.
Employment law has a provision known as “Section 44”. Section 44 allows a worker to refuse to work/refuse to undertake tasks that they believe to be a “serious and imminent” danger.
If you intend to refuse to work on health and safety grounds, it’s very important that you speak to your union representative before or as soon as possible after your refusal.
Read relevant section of Employment Rights Act 1996 on the government website – https://www.legislation.gov.uk/ukpga/1996/18/section/44
Refuge* Workers United 