WASHINGTON (AFP) -- Twenty-seven members of Congress on Wednesday appealed to Dow Chemical Co. (DOW) to pay to clean up the site of the world's worst industrial disaster in Bhopal, India, 25 years ago.

In a letter to the company's chairman in Michigan, the U.S. lawmakers also urged Dow to "immediately" meet survivors' demands for medical and economic rehabilitation and to clean up the soil and water of the site.

The members of Congress also asked the company to send a representative to take part in court proceedings in India.

"Bhopal is widely regarded as the worst industrial disaster in human history, a catastrophe with widespread implications for the chemical industry, globalization and human rights," they said in the letter.

"However, the disaster continues, and is likely to worsen," read the letter, spearheaded by Rep. Frank Pallone, a Democrat from New Jersey.

The tragedy occurred in December 1984 when a storage tank at a pesticide plant run by Union Carbide Corp. - bought by Dow Chemical in 1999 - spewed cyanide gas into the air in Bhopal, immediately killing more than 3,500 slum dwellers.

The members of Congress estimated that another 15,000 people have died since, with 15 more dying each month from the effects of the gas exposure.

Dow says all liabilities were settled in 1989 when Union Carbide paid $470 million to the Indian government, to be allocated to survivors and families of the dead, and that it no longer operates the site.

But activists in Bhopal say the amount is too low and does not account for the after-effects of the gas leak or toxic pollution from before the disaster.

The members of Congress agreed, saying that in both India and the U.S. the polluter, rather than public agencies or taxpayers, should bear responsibility for all environmental damage.