Sir,
I feel you undertake transportation of chemicals in tanker. This is covered by Goods Transport (GTA) Agency Service. As per rule 4 B of Service Tax Rules, 1994, a GTA is required to issue consignment note except when transport of goods by road is exempted. Issue of consignment note is compulsory only for GTA and not all transporters. If the goods transporter does not issue consignment note he is not 'goods transport agency' at all as per definition of GTA in Section 65 B (26) of Finance Act, 1994. Hence rule 4 B will not be applicable. Only in respect of GTA who provides GTA service in respect of transportation of goods by road, where the person liable to pay freight is,-
(I) any factory registered under or governed by the Factories Act, 1948 (63 of 1948);
(II) any society registered under the Societies Registration Act, 1860 (21 of 1860) or under any other law for the time being in force in any part of India;
(III) any co-operative society established by or under any law;
(IV) any dealer of excisable goods, who is registered under the Central Excise Act, 1944 (1 of 1944) or the rules made thereunder;
(V) any body corporate established, by or under any law; or
(VI) any partnership firm whether registered or not under any law including association of persons;
any person who pays or is liable to pay freight either himself or through his agent for the transportation of such goods by road in a goods carriage.
Therefore only when the service provided by GTA the service tax is payable on the basis of reverse charge mechanism. Otherwise service tax is payable by the service provider subject to the limit that the value of service provided is within 10 lakhs rupees during previous year or does not likely to exceed the said limit during current financial year. You have to take registration only when you cross the limit of 9 lakhs.
If the value of service provided by you exceeds ₹ 10 lakhs during previous financial year then you have to take a registration. If you are a GTA and your customers fall in any of category listed above then your customer has to pay service tax on reverse charge mechanism and you customer has to take a registration.