According to article 8 of Decree 93/1999 of 6th April, on waste management procedures, the person responsible for waste is the person, designated by the waste producer or holder, who performs the control, vigilance and information functions concerning waste management. This person must have the necessary knowledge to fulfil their work and, in any case, be a worker of the company acting under the orders and directives of the businessperson or waste producing or holding company.

The administrative responsibility that might be derived from the waste management activity does not lie with the "person responsible for the waste", but the company which, as a waste producer or holder, is the physical person or legal entity that Law 6/1993, regulating waste, makes responsible for guaranteeing its correct management.

In this sense, articles 17 and 24.3 of Law 6/1993 of 15th July, regulating waste, establish that the waste producer and holder are obliged to guarantee that that wastes generated or held are managed correctly, that is, in accordance with the requisites of the law and by an authorised manager.

Failure to fulfil these obligations gives rise to administrative responsibilities which in any case lie with the people obliged, that is, the waste producer or holder, and not other subjects such as the waste controller.

A different matter entirely is the penal responsibility that they might incur concerning the waste when the infringement constitutes an offence according to the articles 325 and following of the Penal Code. In this area the responsibilities lie with the physical person or people who might be responsible for the offence. In this case it is possible to penally blame the waste controller insofar as they have participated in committing the offence.

A by-product is waste as established by the definition given by Law 6/1993 of 15th July, regulating waste: "By-products are waste that can be used directly as raw materials in other productions or as a substitute for commercial products, and which are recoverable without any need to subjecting them to treatment operations".

Although they are waste, as they can be used directly, by-products are affected by a different legal system.

In this sense, Decree 93/1999 concerning waste management procedures establishes in article 29 that by-products are excluded from the waste control documentary obligations: Acceptance sheet and Consignment note. Furthermore, the mentioned article regulates the following by-product declaration procedure:

"The producer or holder and the receiver of a waste must give the Agència de Residus de Catalunya a copy of the contract signed between the parties for the corresponding by-product declaration, agreeing on the purchase and sale of the waste and an explanatory report giving its description and composition, the description of the receiver process and the raw material to be replaced".

"The Agència de Residus de Catalunya declares the waste a by-product, identifies it with the process in which it is to be used and states the producer or receiver company. This declaration has a maximum duration of five years, after which it lies without effect".

"The companies using the waste referred to in the previous aside do not have to register in the General Register of Waste Management of Catalonia. The companies producing and receiving this waste must state their transfer in their annual industrial waste declarations."

Article 15 of Law 6/1993 of 15th July, regulating waste, deals with the concept of degraded space (which is a wider concept that that of contaminated soil) and establishes a system of responsibilities for its regeneration:

The mentioned article establishes that the person directly responsible for regenerating a degraded space is the person who has effected the unloading and, alongside them, the waste producer or holder. Furthermore, the owner of the land where the unloading has taken place or the holder of the affected public lands is also subsidiarily responsible.

Law 10/1998 of 21st April on waste establishes the basic state regulation on contaminated soils in its title V. The system of obligations and responsibilities established in Law 10/1998 on waste establishes that the declaration of a soil as contaminated involves the obligation to perform all necessary cleaning and recovery operations.

Those causing the pollution are responsible for the cleaning and recovery operations, and when there are several of them, the holder of the contaminated soils and the non holder owners will reply there for together and subsidiarily, in this order.

Royal Decree 9/2005 of 14th January 2005, which establishes the list of activities that are potentially harmful for the soil and the criteria and standards for the contaminated soil declaration, has supposed the regulatory development provided in Law 10/1998.

This Royal Decree regulates the obligations of the activities that are potentially contaminating of the soil and establishes the criteria that must enable the declaration of contaminated soils by the competent bodies of the Autonomous Communities.

Decree 34/1996 of 9th January, in approval of the Catalonian waste catalogue, in the text given by Decree 92/1999, establishes in article 5.2 that the wastes caused, acquired intracommunitarily or that are imported must be managed according to the determinations of the catalogue.

However, the contradictory proceeding regulated in article 6 of the same Decree 34/1996 allows a change in the management established by the catalogue if the waste producer or holder provides the competent environmental body with all pertinent documentary proof to certify the possibility of managing the waste in a way that is more environmentally beneficial.

Current regulations concerning waste do not give an overall reply to this question, but are limited to regulating certain terms for certain documentary obligations. Therefore, it is necessary to highlight:

• Decree 93/1999 concerning waste management procedures establishes that the Acceptance sheet expires automatically after five years, so it is understood that it has to be maintained while in force.
• As for the destination sheet, Decree 93/1999 establishes a time of two years, after which it may be destroyed.
• Decree 220/2001, concerning the management of cattle manure, establishes that the cattle manure management books must be preserved for the four years following the date of the last note or ceasing of activity. Likewise, it is established that the producer must preserve the waste delivery slips for at least four years in his management book along with the original certificate signed by the carrier and the receiver, whenever necessary.
• Concerning the state regulations, Law 10/1998 on waste establishes the obligation of the manager to preserve the register of managed waste each year for the following five years.
• For its part, Royal Decree 833/1988 regulates the obligation of the producer and hazardous waste managers to keep the registers for five years, as well as the annual declaration, the annual activity report and the waste control and consignment documentation.

Having seen this, in order to simplify matters, as a general rule it is possible to establish that the obligation of preserving waste control documentation is for five years.