One month after the devastating March 11 earthquake and tsunami hit Japan, another strong aftershock today briefly set off a tsunami warning and knocked out cooling at the crippled Fukushima Daiichi nuclear power plant for almost an hour, the New York Times reports.

The United States Geological Society (USGS) reported the aftershock at magnitude 6.6.

Earlier in the day the Japanese government had said it was preparing to expand the evacuation zone around the nuclear facility to address concerns over long-term exposure to radiation.

An article in the New York Times over the weekend discusses how Japanese workers risk hazardous conditions and lax safety practices for a temporary job.

A recent blog post by Juliana Olsson on PropertyCasualty360.com noted that many Japanese workers accept the conditions and risks because of the pay. Olsson wrote:

It is troubling that there are no unions and no workers’ compensation in place for many nuclear power plant laborers. At the same time, some think that regardless of the legal rights of the workers, people should not be put in such extreme situations.”

In the United States federal workers at nuclear plants may be covered under the Energy Employees Occupational Illness Compensation Program (EEOICP). The program, which started in 2001, provides compensation and health benefits to eligible department of energy nuclear weapons workers (including employees, former employees, contractors and subcontractors). There is also the state-based workers’ compensation system.

Check out the I.I.I. primer to find out more about how insurance coverage for nuclear accidents works in the United States.