Volunteer coastguard teams around the UK have withdrawn from responding to call-outs following a row over compensation for injuries.
The volunteers - usually on permanent standby - say they are not fully covered by the insurance policy of the Maritime and Coastguard Agency (MCA).
The dispute began with the case of a Pembrokeshire man injured in a cliff rescue, causing him to lose his job.
He will only get a temporary payment of less than half his old salary.
Teams in West Wales, Western Scotland and along the Bristol Channel withdrew their services at midnight on Thursday, saying they would not work until the MCA agreed to give them full compensation if they were injured and disabled during a rescue operation.
In total so far, 21 out of 378 teams have withdrawn their services, the MCA said.
The MCA said it had put contingency plans in place for the action, which began on Tuesday.
It said it was "disappointed" by the stoppage, and hoped it would be resolved at a meeting planned for Thursday evening.
If the issues are not resolved at the meeting, between MCA management and volunteers, the coastguards say more teams are likely to join the stoppage of emergency responses.
The case of Pembrokeshire rescuer Brian MacFarlane, 38, was the catalyst for the dispute.
He was seriously injured while rescuing an animal from a cliff face four years ago, and subsequently lost his job as a residential social worker.
He and his colleagues say the case revealed how vulnerable they were.
Mr MacFarlane said: "I am very unhappy about all of this because it is not right. It is not the way people should be treated.
"These people are putting their lives on the line - day in, day out - very often in the worst weather conditions possible, carrying the equipment, looking for people who have got lost... and any one of those coastguards and rescue officers could get blown off a cliff or fall down a hole.
"To be treated like this, frankly, is not right and not fair."
"I do feel gutted and I feel gutted for the other coastguard officers around the country, because they could potentially find themselves in the self-same situation because the insurance policy is not fit for purpose."
Brian MacFarlane was injured rescuing an animal four years ago
Fishguard station officer John Davies said: "We are ordinary people who do an extraordinary thing. We are on standby 24 hours a day, 365 days a year to risk our lives to rescue people.
"But we are not willing to risk our livelihoods and the welfare of our families.
"It is with great regret and reluctance that we have taken these steps."
Fred Caygill from the MCA said the civil service injuries benefits scheme which covers the coastguards was a national scheme which covered all civil servants.
"It is therefore not within the MCA's gift to make its own changes to the scheme, although the MCA will be able to represent the view of volunteer coastguards to central government," he added.